diff --git a/StarterNG/Domain/Settings/SimulatorSettings.cs b/StarterNG/Domain/Settings/SimulatorSettings.cs
index a93169e..e1dea3c 100644
--- a/StarterNG/Domain/Settings/SimulatorSettings.cs
+++ b/StarterNG/Domain/Settings/SimulatorSettings.cs
@@ -35,6 +35,7 @@ public sealed class SimulatorSettings
     public bool DebugMode;
     public bool VirtualShunting = true;
     public bool LogMissingVehicleFiles;
+    public bool DeveloperTools;
 
     public int RenderEngine;
     public int Width = 1280;
diff --git a/StarterNG/Infrastructure/Settings/SettingsSerializer.cs b/StarterNG/Infrastructure/Settings/SettingsSerializer.cs
index 498a50f..79260d8 100644
--- a/StarterNG/Infrastructure/Settings/SettingsSerializer.cs
+++ b/StarterNG/Infrastructure/Settings/SettingsSerializer.cs
@@ -56,6 +56,7 @@ public sealed class SettingsSerializer
         s.DebugMode = c.GetBool("debugmode", false);
         s.VirtualShunting = c.GetBool("ai.trainman", true);
         s.LogMissingVehicleFiles = c.GetBool("starter.logmissingvehicles", false);
+        s.DeveloperTools = c.GetBool("starter.developertools", false);
 
         s.RenderEngine = IndexOf(SimulatorSettings.RenderEngines, c.GetString("gfxrenderer", "full"), 0);
         s.Width = c.GetInt("width", 1280);
@@ -195,6 +196,7 @@ public sealed class SettingsSerializer
         c.SetBool("debugmode", s.DebugMode);
         c.SetBool("ai.trainman", s.VirtualShunting);
         c.SetBool("starter.logmissingvehicles", s.LogMissingVehicleFiles);
+        c.SetBool("starter.developertools", s.DeveloperTools);
 
         c.Set("gfxrenderer", SimulatorSettings.RenderEngines[Clamp(s.RenderEngine, 0, SimulatorSettings.RenderEngines.Length - 1)]);
         c.SetInt("width", s.Width);
diff --git a/StarterNG/MainWindow.axaml b/StarterNG/MainWindow.axaml
index 9d2b8bc..c631bd1 100644
--- a/StarterNG/MainWindow.axaml
+++ b/StarterNG/MainWindow.axaml
@@ -37,6 +37,10 @@
                                      Tag="settings"
                                      IsCheckedChanged="Nav_OnCheckedChanged"
                                      Content="{Binding [NavSettings], Source={x:Static starterNg:App.Loc}}" />
+                        <RadioButton x:Name="NavDeveloper" GroupName="nav" Theme="{StaticResource NavTab}"
+                                     Tag="developer" IsVisible="False"
+                                     IsCheckedChanged="Nav_OnCheckedChanged"
+                                     Content="{Binding [NavDeveloper], Source={x:Static starterNg:App.Loc}}" />
                         <Button Classes="Basic" Click="openLastLogClick" Width="48" Cursor="Hand"
                                 HorizontalContentAlignment="Center"
                                 ToolTip.Tip="{Binding [ShowLatestLogTooltip], Source={x:Static starterNg:App.Loc}}">
@@ -93,6 +97,7 @@
             <views:Scenarios x:Name="ScenariosView" />
             <views:Depot x:Name="DepotView" IsVisible="False" />
             <views:Settings x:Name="SettingsView" IsVisible="False" />
+            <views:Developer x:Name="DeveloperView" IsVisible="False" />
         </Panel>
     </DockPanel>
 </Window>
diff --git a/StarterNG/MainWindow.axaml.cs b/StarterNG/MainWindow.axaml.cs
index cd2a72f..beda717 100644
--- a/StarterNG/MainWindow.axaml.cs
+++ b/StarterNG/MainWindow.axaml.cs
@@ -56,6 +56,8 @@ public partial class MainWindow : Window
         startButton.AddHandler(PointerReleasedEvent, StartButton_OnRightClick,
                                RoutingStrategies.Tunnel);
 
+        SettingsView.DeveloperToolsChanged += ApplyDeveloperTab;
+
         SettingsView.ThumbnailSizeChanged += () =>
         {
             DepotView.RefreshConsistView();
@@ -172,7 +174,7 @@ public partial class MainWindow : Window
         if (sender is not RadioButton { IsChecked: true } rb)
             return;
 
-        if (ScenariosView is null || DepotView is null || SettingsView is null)
+        if (ScenariosView is null || DepotView is null || SettingsView is null || DeveloperView is null)
             return;
 
         ShowPage(rb.Tag as string);
@@ -184,11 +186,31 @@ public partial class MainWindow : Window
         ScenariosView.IsVisible = page == "scenarios";
         DepotView.IsVisible = page == "depot";
         SettingsView.IsVisible = page == "settings";
+        DeveloperView.IsVisible = page == "developer";
+
+        if (DeveloperView.IsVisible)
+            DeveloperView.Refresh();
+    }
+
+    /// <summary>
+    /// Shows or hides the developer tab. Switching it off while it is the open one
+    /// hands the window back to the scenarios, so the top bar never ends up with
+    /// nothing selected.
+    /// </summary>
+    private void ApplyDeveloperTab()
+    {
+        bool wanted = AppServices.Current.Settings.DeveloperTools;
+        NavDeveloper.IsVisible = wanted;
+
+        if (!wanted && NavDeveloper.IsChecked == true)
+            NavScenarios.IsChecked = true;
     }
 
     private void ApplyInitialNav()
     {
-        foreach (var rb in new[] { NavScenarios, NavDepot, NavSettings })
+        ApplyDeveloperTab();
+
+        foreach (var rb in new[] { NavScenarios, NavDepot, NavSettings, NavDeveloper })
             if (rb.IsChecked == true)
             {
                 ShowPage(rb.Tag as string);
diff --git a/StarterNG/Views/Developer.axaml b/StarterNG/Views/Developer.axaml
new file mode 100644
index 0000000..3dc1bc7
--- /dev/null
+++ b/StarterNG/Views/Developer.axaml
@@ -0,0 +1,65 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             xmlns:starterNg="clr-namespace:StarterNG"
+             x:CompileBindings="True"
+             mc:Ignorable="d" d:DesignWidth="1000" d:DesignHeight="700"
+             x:Class="StarterNG.Views.Developer">
+    <!-- Read-only view of what the starter made of the installation: the counts a
+         package author needs before slicing anything out of it, and the state of
+         the JSON copy those packages will be generated from. -->
+    <StackPanel Margin="3" Spacing="3">
+        <Border Background="{StaticResource CarbonPanelBg}" BorderBrush="{StaticResource CarbonBorderLight}"
+                BorderThickness="1" CornerRadius="2" Padding="10" HorizontalAlignment="Left" MinWidth="440">
+            <StackPanel Spacing="8">
+                <TextBlock Text="{Binding [DevDatabase], Source={x:Static starterNg:App.Loc}}"
+                           FontWeight="Bold" FontSize="14" />
+
+                <Grid ColumnDefinitions="190,*" RowDefinitions="Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto"
+                      RowSpacing="4">
+                    <TextBlock Grid.Row="0" Grid.Column="0" Foreground="{StaticResource CarbonFgDim}"
+                               Text="{Binding [DevVehicles], Source={x:Static starterNg:App.Loc}}" />
+                    <TextBlock Grid.Row="0" Grid.Column="1" x:Name="VehiclesValue" />
+
+                    <TextBlock Grid.Row="1" Grid.Column="0" Foreground="{StaticResource CarbonFgDim}"
+                               Text="{Binding [DevLiveries], Source={x:Static starterNg:App.Loc}}" />
+                    <TextBlock Grid.Row="1" Grid.Column="1" x:Name="LiveriesValue" />
+
+                    <TextBlock Grid.Row="2" Grid.Column="0" Foreground="{StaticResource CarbonFgDim}"
+                               Text="{Binding [DevGroups], Source={x:Static starterNg:App.Loc}}" />
+                    <TextBlock Grid.Row="2" Grid.Column="1" x:Name="GroupsValue" />
+
+                    <TextBlock Grid.Row="3" Grid.Column="0" Foreground="{StaticResource CarbonFgDim}"
+                               Text="{Binding [DevSets], Source={x:Static starterNg:App.Loc}}" />
+                    <TextBlock Grid.Row="3" Grid.Column="1" x:Name="SetsValue" />
+
+                    <TextBlock Grid.Row="4" Grid.Column="0" Foreground="{StaticResource CarbonFgDim}"
+                               Text="{Binding [DevFiles], Source={x:Static starterNg:App.Loc}}" />
+                    <TextBlock Grid.Row="4" Grid.Column="1" x:Name="FilesValue" />
+
+                    <TextBlock Grid.Row="5" Grid.Column="0" Foreground="{StaticResource CarbonFgDim}"
+                               Text="{Binding [DevSource], Source={x:Static starterNg:App.Loc}}" />
+                    <TextBlock Grid.Row="5" Grid.Column="1" x:Name="SourceValue" />
+
+                    <TextBlock Grid.Row="6" Grid.Column="0" Foreground="{StaticResource CarbonFgDim}"
+                               Text="{Binding [DevWritten], Source={x:Static starterNg:App.Loc}}" />
+                    <TextBlock Grid.Row="6" Grid.Column="1" x:Name="WrittenValue" />
+
+                    <TextBlock Grid.Row="7" Grid.Column="0" Foreground="{StaticResource CarbonFgDim}"
+                               Text="{Binding [DevLocation], Source={x:Static starterNg:App.Loc}}"
+                               VerticalAlignment="Top" />
+                    <SelectableTextBlock Grid.Row="7" Grid.Column="1" x:Name="LocationValue"
+                                         TextWrapping="Wrap" FontSize="11" />
+                </Grid>
+
+                <StackPanel Orientation="Horizontal" Spacing="8">
+                    <Button x:Name="RebuildButton" Click="RebuildButton_OnClick" Cursor="Hand"
+                            Content="{Binding [DevRebuild], Source={x:Static starterNg:App.Loc}}" />
+                    <TextBlock x:Name="RebuildStatus" VerticalAlignment="Center"
+                               Foreground="{StaticResource CarbonFgDim}" />
+                </StackPanel>
+            </StackPanel>
+        </Border>
+    </StackPanel>
+</UserControl>
diff --git a/StarterNG/Views/Developer.axaml.cs b/StarterNG/Views/Developer.axaml.cs
new file mode 100644
index 0000000..cac678d
--- /dev/null
+++ b/StarterNG/Views/Developer.axaml.cs
@@ -0,0 +1,78 @@
+using System;
+using System.Globalization;
+using System.Linq;
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+using Avalonia.Markup.Xaml;
+using StarterNG.Application;
+using StarterNG.Domain.Vehicles;
+
+namespace StarterNG.Views;
+
+/// <summary>
+/// The developer tab: what the starter read out of the installation, and the state
+/// of the JSON copy it keeps of it. Read-only apart from rebuilding that copy.
+/// </summary>
+public partial class Developer : UserControl
+{
+    public Developer()
+    {
+        InitializeComponent();
+    }
+
+    private void InitializeComponent() => AvaloniaXamlLoader.Load(this);
+
+    /// <summary>Fills the panel from the catalogue as it stands right now.</summary>
+    public void Refresh()
+    {
+        var catalog = AppServices.Current.Library.Vehicles;
+        var status = AppServices.Current.VehicleCache.Status;
+
+        VehiclesValue.Text = Count(catalog.TextureByUuid.Values
+                                          .Select(texture => texture.Directory)
+                                          .Distinct(StringComparer.OrdinalIgnoreCase)
+                                          .Count());
+        LiveriesValue.Text = Wrecks(catalog);
+        GroupsValue.Text = Count(catalog.GroupsById.Count);
+        SetsValue.Text = Count(catalog.Sets.Count);
+        FilesValue.Text = Count(status.Sources);
+        SourceValue.Text = App.Loc[status.ServedFromCopy ? "DevSourceCopy" : "DevSourceTextures"];
+        WrittenValue.Text = status.Written is { } written
+            ? written.ToLocalTime().ToString("yyyy-MM-dd HH:mm", CultureInfo.InvariantCulture)
+            : "-";
+        LocationValue.Text = status.Directory;
+        RebuildStatus.Text = "";
+    }
+
+    /// <summary>
+    /// Rebuilds the copy on disk without disturbing the catalogue the other tabs
+    /// are already drawn from - the vehicles on screen keep pointing at the entries
+    /// they were built with.
+    /// </summary>
+    private void RebuildButton_OnClick(object? sender, RoutedEventArgs e)
+    {
+        RebuildButton.IsEnabled = false;
+        try
+        {
+            int liveries = AppServices.Current.VehicleCache
+                                      .Rebuild(new VehicleCatalog(AppServices.Current.MiniTextures));
+            Refresh();
+            RebuildStatus.Text = $"{App.Loc["DevRebuilt"]} ({liveries})";
+        }
+        finally
+        {
+            RebuildButton.IsEnabled = true;
+        }
+    }
+
+    /// <summary>Liveries offered, saying so when wrecks are being held back.</summary>
+    private static string Wrecks(VehicleCatalog catalog)
+    {
+        int wrecks = catalog.TextureByUuid.Count - catalog.Textures.Count;
+        return wrecks > 0
+            ? $"{Count(catalog.Textures.Count)}  (+{Count(wrecks)} {App.Loc["DevWrecks"]})"
+            : Count(catalog.Textures.Count);
+    }
+
+    private static string Count(int value) => value.ToString(CultureInfo.InvariantCulture);
+}
diff --git a/StarterNG/Views/Settings.axaml b/StarterNG/Views/Settings.axaml
index d441d5a..17e0115 100644
--- a/StarterNG/Views/Settings.axaml
+++ b/StarterNG/Views/Settings.axaml
@@ -144,6 +144,9 @@
                                     <ctl:SettingRow ConfigKey="starter.logmissingvehicles" Description="{Binding [LogMissingVehicleFilesDesc], Source={x:Static starterNg:App.Loc}}">
                                         <CheckBox x:Name="LogMissingVehicleFilesCb" Content="{Binding [LogMissingVehicleFiles], Source={x:Static starterNg:App.Loc}}" />
                                     </ctl:SettingRow>
+                                    <ctl:SettingRow ConfigKey="starter.developertools" Description="{Binding [DeveloperToolsDesc], Source={x:Static starterNg:App.Loc}}">
+                                        <CheckBox x:Name="DeveloperToolsCb" Content="{Binding [DeveloperTools], Source={x:Static starterNg:App.Loc}}" />
+                                    </ctl:SettingRow>
                                 </StackPanel>
                             </ctl:SettingsSection>
                         </StackPanel>
diff --git a/StarterNG/Views/Settings.axaml.cs b/StarterNG/Views/Settings.axaml.cs
index 0676034..f809f28 100644
--- a/StarterNG/Views/Settings.axaml.cs
+++ b/StarterNG/Views/Settings.axaml.cs
@@ -34,9 +34,15 @@ public partial class Settings : UserControl, ISettingsCapture
     /// </summary>
     public event Action? ThumbnailSizeChanged;
 
+    /// <summary>Raised when the developer tab is switched on or off, so the top bar can follow.</summary>
+    public event Action? DeveloperToolsChanged;
+
     /// <summary>Thumbnail size the other tabs were last drawn at.</summary>
     private bool _drawnThumbs = AppServices.Current.Settings.LargeThumbnails;
 
+    /// <summary>Whether the top bar was last drawn with the developer tab on it.</summary>
+    private bool _shownDeveloperTools = AppServices.Current.Settings.DeveloperTools;
+
     public Settings()
     {
         InitializeComponent();
@@ -199,6 +205,7 @@ public partial class Settings : UserControl, ISettingsCapture
             DebugModeCb.IsChecked = s.DebugMode;
             VirtualShuntingCb.IsChecked = s.VirtualShunting;
             LogMissingVehicleFilesCb.IsChecked = s.LogMissingVehicleFiles;
+            DeveloperToolsCb.IsChecked = s.DeveloperTools;
 
             RenderEngineCb.SelectedIndex = s.RenderEngine;
             SelectResolution(s.Width, s.Height);
@@ -297,6 +304,7 @@ public partial class Settings : UserControl, ISettingsCapture
         s.DebugMode = IsChecked(DebugModeCb);
         s.VirtualShunting = IsChecked(VirtualShuntingCb);
         s.LogMissingVehicleFiles = IsChecked(LogMissingVehicleFilesCb);
+        s.DeveloperTools = IsChecked(DeveloperToolsCb);
 
         s.RenderEngine = Math.Max(0, RenderEngineCb.SelectedIndex);
         ReadResolution(s);
@@ -373,12 +381,23 @@ public partial class Settings : UserControl, ISettingsCapture
         AppServices.Current.SettingsStore.Save();
         KeyboardConfig.Instance.Save();
         RedrawThumbnailsIfNeeded();
+        RedrawNavIfNeeded();
         _dirty = false;
         UpdateSaveState();
         if (SaveStatus is not null)
             SaveStatus.Text = App.Loc["SettingsSaved"];
     }
 
+    private void RedrawNavIfNeeded()
+    {
+        bool developer = AppServices.Current.Settings.DeveloperTools;
+        if (developer == _shownDeveloperTools)
+            return;
+
+        _shownDeveloperTools = developer;
+        DeveloperToolsChanged?.Invoke();
+    }
+
     private void RedrawThumbnailsIfNeeded()
     {
         bool large = AppServices.Current.Settings.LargeThumbnails;
diff --git a/StarterNG/startercfg/lang/cz.xml b/StarterNG/startercfg/lang/cz.xml
index 5c95d84..5e4a10c 100644
--- a/StarterNG/startercfg/lang/cz.xml
+++ b/StarterNG/startercfg/lang/cz.xml
@@ -7,6 +7,7 @@
     <String key="NavScenarios">Scénáře</String>
     <String key="NavDepot">Depo</String>
     <String key="NavSettings">Nastavení</String>
+    <String key="NavDeveloper">Developer</String>
     <String key="NavControls">Ovládání</String>
     <String key="Help">Nápověda</String>
     <String key="HelpWiki">Wiki MaSzyna</String>
@@ -334,6 +335,7 @@
     <String key="DebugMode">Režim ladění (testovací režim)</String>
     <String key="VirtualShunting">Virtuální posun</String>
     <String key="LogMissingVehicleFiles">Zaznamenat chybějící soubory vozidel při exportu</String>
+    <String key="DeveloperTools">Show the package author's tab</String>
 
     <String key="Graphic">Grafika</String>
     <String key="RenderEngine">Vykreslovací engine</String>
@@ -584,4 +586,20 @@
     <String key="ShortcutMember">Vybrat člen ve spojené jednotce</String>
     <String key="ShortcutMoveVehicle">Posunout vozidlo v soupravě</String>
     <String key="ShortcutCardMenu">Otevřít nabídku vozidla</String>
+
+    <!-- Package author's tab - awaiting translation -->
+    <String key="DevDatabase">Vehicle database</String>
+    <String key="DevVehicles">Vehicle folders</String>
+    <String key="DevLiveries">Liveries</String>
+    <String key="DevWrecks">wrecks</String>
+    <String key="DevGroups">Groups</String>
+    <String key="DevSets">Fixed sets</String>
+    <String key="DevFiles">textures.txt files</String>
+    <String key="DevSource">Read from</String>
+    <String key="DevSourceCopy">the starter's copy</String>
+    <String key="DevSourceTextures">textures.txt files</String>
+    <String key="DevWritten">Copy written</String>
+    <String key="DevLocation">Copy folder</String>
+    <String key="DevRebuild">Rebuild copy</String>
+    <String key="DevRebuilt">Rebuilt</String>
 </Language>
diff --git a/StarterNG/startercfg/lang/en.xml b/StarterNG/startercfg/lang/en.xml
index 36f7335..197e9d6 100644
--- a/StarterNG/startercfg/lang/en.xml
+++ b/StarterNG/startercfg/lang/en.xml
@@ -7,6 +7,7 @@
     <String key="NavScenarios">Scenarios</String>
     <String key="NavDepot">Depot</String>
     <String key="NavSettings">Settings</String>
+    <String key="NavDeveloper">Developer</String>
     <String key="NavControls">Controls</String>
     <String key="Help">Help</String>
     <String key="HelpWiki">MaSzyna wiki</String>
@@ -340,6 +341,8 @@
     <String key="VirtualShuntingDesc">Enables an AI assistant for coupling, uncoupling and simple shunting moves while the vehicle is stopped.</String>
     <String key="LogMissingVehicleFiles">Log missing vehicle files during export</String>
     <String key="LogMissingVehicleFilesDesc">Writes vehicles the starter could not find into the log.</String>
+    <String key="DeveloperTools">Show the package author's tab</String>
+    <String key="DeveloperToolsDesc">Adds a tab with the state of the vehicle database, for preparing rolling stock packages.</String>
 
     <String key="Graphic">Graphics</String>
     <String key="RenderEngine">Render engine</String>
@@ -619,4 +622,20 @@
     <String key="ShortcutMember">Pick a car inside a coupled unit</String>
     <String key="ShortcutMoveVehicle">Move the vehicle along the consist</String>
     <String key="ShortcutCardMenu">Open the vehicle menu</String>
+
+    <!-- Package author's tab -->
+    <String key="DevDatabase">Vehicle database</String>
+    <String key="DevVehicles">Vehicle folders</String>
+    <String key="DevLiveries">Liveries</String>
+    <String key="DevWrecks">wrecks</String>
+    <String key="DevGroups">Groups</String>
+    <String key="DevSets">Fixed sets</String>
+    <String key="DevFiles">textures.txt files</String>
+    <String key="DevSource">Read from</String>
+    <String key="DevSourceCopy">the starter's copy</String>
+    <String key="DevSourceTextures">textures.txt files</String>
+    <String key="DevWritten">Copy written</String>
+    <String key="DevLocation">Copy folder</String>
+    <String key="DevRebuild">Rebuild copy</String>
+    <String key="DevRebuilt">Rebuilt</String>
 </Language>
diff --git a/StarterNG/startercfg/lang/hu.xml b/StarterNG/startercfg/lang/hu.xml
index b05ebd4..637c517 100644
--- a/StarterNG/startercfg/lang/hu.xml
+++ b/StarterNG/startercfg/lang/hu.xml
@@ -7,6 +7,7 @@
     <String key="NavScenarios">Forgatókönyvek</String>
     <String key="NavDepot">Fűtőház</String>
     <String key="NavSettings">Beállítások</String>
+    <String key="NavDeveloper">Developer</String>
     <String key="NavControls">Irányítás</String>
     <String key="Help">Súgó</String>
     <String key="HelpWiki">MaSzyna wiki</String>
@@ -334,6 +335,7 @@
     <String key="DebugMode">Hibakeresési mód (teszt mód)</String>
     <String key="VirtualShunting">Virtuális tolatás</String>
     <String key="LogMissingVehicleFiles">Hiányzó járműfájlok naplózása exportáláskor</String>
+    <String key="DeveloperTools">Show the package author's tab</String>
 
     <String key="Graphic">Grafika</String>
     <String key="RenderEngine">Megjelenítő motor</String>
@@ -584,4 +586,20 @@
     <String key="ShortcutMember">Tag kiválasztása kapcsolt egységen belül</String>
     <String key="ShortcutMoveVehicle">Jármű mozgatása a szerelvényben</String>
     <String key="ShortcutCardMenu">Jármű menüjének megnyitása</String>
+
+    <!-- Package author's tab - awaiting translation -->
+    <String key="DevDatabase">Vehicle database</String>
+    <String key="DevVehicles">Vehicle folders</String>
+    <String key="DevLiveries">Liveries</String>
+    <String key="DevWrecks">wrecks</String>
+    <String key="DevGroups">Groups</String>
+    <String key="DevSets">Fixed sets</String>
+    <String key="DevFiles">textures.txt files</String>
+    <String key="DevSource">Read from</String>
+    <String key="DevSourceCopy">the starter's copy</String>
+    <String key="DevSourceTextures">textures.txt files</String>
+    <String key="DevWritten">Copy written</String>
+    <String key="DevLocation">Copy folder</String>
+    <String key="DevRebuild">Rebuild copy</String>
+    <String key="DevRebuilt">Rebuilt</String>
 </Language>
diff --git a/StarterNG/startercfg/lang/pl.xml b/StarterNG/startercfg/lang/pl.xml
index 77e280b..c32dfe8 100644
--- a/StarterNG/startercfg/lang/pl.xml
+++ b/StarterNG/startercfg/lang/pl.xml
@@ -7,6 +7,7 @@
     <String key="NavScenarios">Scenariusze</String>
     <String key="NavDepot">Zajezdnia</String>
     <String key="NavSettings">Ustawienia</String>
+    <String key="NavDeveloper">Deweloper</String>
     <String key="NavControls">Sterowanie</String>
     <String key="Help">Pomoc</String>
     <String key="HelpWiki">Wiki MaSzyna</String>
@@ -340,6 +341,8 @@
     <String key="VirtualShuntingDesc">Włącza asystenta AI do sprzęgania, rozprzęgania i prostych manewrów, gdy pojazd stoi.</String>
     <String key="LogMissingVehicleFiles">Zapisuj w logu brakujące pliki pojazdów podczas eksportu</String>
     <String key="LogMissingVehicleFilesDesc">Zapisuje w logu pojazdy, których starter nie znalazł.</String>
+    <String key="DeveloperTools">Pokaż zakładkę dla twórców paczek</String>
+    <String key="DeveloperToolsDesc">Dodaje zakładkę ze stanem bazy pojazdów, przydatną przy przygotowywaniu paczek z taborem.</String>
 
     <String key="Graphic">Grafika</String>
     <String key="RenderEngine">Silnik renderowania</String>
@@ -619,4 +622,20 @@
     <String key="ShortcutMember">Wybierz człon w zespolonej jednostce</String>
     <String key="ShortcutMoveVehicle">Przesuń pojazd w składzie</String>
     <String key="ShortcutCardMenu">Otwórz menu pojazdu</String>
+
+    <!-- Zakladka dla tworcow paczek -->
+    <String key="DevDatabase">Baza pojazdów</String>
+    <String key="DevVehicles">Katalogi pojazdów</String>
+    <String key="DevLiveries">Malowania</String>
+    <String key="DevWrecks">wraki</String>
+    <String key="DevGroups">Grupy</String>
+    <String key="DevSets">Zespoły stałe</String>
+    <String key="DevFiles">Pliki textures.txt</String>
+    <String key="DevSource">Wczytano z</String>
+    <String key="DevSourceCopy">kopii startera</String>
+    <String key="DevSourceTextures">plików textures.txt</String>
+    <String key="DevWritten">Kopia zapisana</String>
+    <String key="DevLocation">Katalog kopii</String>
+    <String key="DevRebuild">Odbuduj kopię</String>
+    <String key="DevRebuilt">Odbudowano</String>
 </Language>
diff --git a/StarterNG/startercfg/lang/ru.xml b/StarterNG/startercfg/lang/ru.xml
index 9c4aed0..786ea12 100644
--- a/StarterNG/startercfg/lang/ru.xml
+++ b/StarterNG/startercfg/lang/ru.xml
@@ -7,6 +7,7 @@
     <String key="NavScenarios">Сценарии</String>
     <String key="NavDepot">Депо</String>
     <String key="NavSettings">Настройки</String>
+    <String key="NavDeveloper">Developer</String>
     <String key="NavControls">Управление</String>
     <String key="Help">Справка</String>
     <String key="HelpWiki">Вики MaSzyna</String>
@@ -334,6 +335,7 @@
     <String key="DebugMode">Режим отладки (тестовый режим)</String>
     <String key="VirtualShunting">Виртуальный манёвр</String>
     <String key="LogMissingVehicleFiles">Записывать в журнал отсутствующие файлы состава при экспорте</String>
+    <String key="DeveloperTools">Show the package author's tab</String>
 
     <String key="Graphic">Графика</String>
     <String key="RenderEngine">Движок отрисовки</String>
@@ -584,4 +586,20 @@
     <String key="ShortcutMember">Выбрать секцию в сцепленной единице</String>
     <String key="ShortcutMoveVehicle">Переместить вагон в составе</String>
     <String key="ShortcutCardMenu">Открыть меню вагона</String>
+
+    <!-- Package author's tab - awaiting translation -->
+    <String key="DevDatabase">Vehicle database</String>
+    <String key="DevVehicles">Vehicle folders</String>
+    <String key="DevLiveries">Liveries</String>
+    <String key="DevWrecks">wrecks</String>
+    <String key="DevGroups">Groups</String>
+    <String key="DevSets">Fixed sets</String>
+    <String key="DevFiles">textures.txt files</String>
+    <String key="DevSource">Read from</String>
+    <String key="DevSourceCopy">the starter's copy</String>
+    <String key="DevSourceTextures">textures.txt files</String>
+    <String key="DevWritten">Copy written</String>
+    <String key="DevLocation">Copy folder</String>
+    <String key="DevRebuild">Rebuild copy</String>
+    <String key="DevRebuilt">Rebuilt</String>
 </Language>