Looks like the Rider plugin (the one built into the editor, I didn’t add anything) is preventing the External Tools tab from displaying any content
NullReferenceException: Object reference not set to an instance of an object
Packages.Rider.Editor.EditorPluginInterop.InitEntryPoint () (at <072369e179f6469db1efdb207452957c>:0)
Packages.Rider.Editor.RiderInitializer.Initialize (System.String editorPath) (at <072369e179f6469db1efdb207452957c>:0)
Packages.Rider.Editor.RiderScriptEditor..cctor () (at <072369e179f6469db1efdb207452957c>:0)
Rethrow as TypeInitializationException: The type initializer for 'Packages.Rider.Editor.RiderScriptEditor' threw an exception.
Unity.CodeEditor.CodeEditor.<GetFoundScriptEditorPaths>m__0 (Unity.CodeEditor.IExternalCodeEditor codeEditor) (at C:/buildslave/unity/build/Editor/Mono/CodeEditor/CodeEditor.cs:135)
System.Linq.Enumerable+SelectManySingleSelectorIterator`2[TSource,TResult].MoveNext () (at <b7efe7e6e548497fac3c4a6049a0a4b6>:0)
Unity.CodeEditor.CodeEditor.GetFoundScriptEditorPaths () (at C:/buildslave/unity/build/Editor/Mono/CodeEditor/CodeEditor.cs:135)
UnityEditor.PreferencesProvider.ReadPreferences () (at C:/buildslave/unity/build/Editor/Mono/PreferencesWindow/PreferencesSettingsProviders.cs:781)
UnityEditor.PreferencesProvider.OnActivate (System.String searchContext, UnityEngine.UIElements.VisualElement rootElement) (at C:/buildslave/unity/build/Editor/Mono/PreferencesWindow/PreferencesSettingsProviders.cs:186)
UnityEditor.SettingsWindow.ProviderChanged (UnityEditor.SettingsProvider lastSelectedProvider, UnityEditor.SettingsProvider newlySelectedProvider) (at C:/buildslave/unity/build/Editor/Mono/Settings/SettingsWindow.cs:237)
UnityEditor.SettingsTreeView.SelectionChanged (System.Collections.Generic.IList`1[T] selectedIds) (at C:/buildslave/unity/build/Editor/Mono/Settings/SettingsTreeView.cs:66)
UnityEditor.IMGUI.Controls.TreeViewController.NotifyListenersThatSelectionChanged () (at C:/buildslave/unity/build/Editor/Mono/GUI/TreeView/TreeViewController.cs:442)
UnityEditor.IMGUI.Controls.TreeViewController.NewSelectionFromUserInteraction (System.Collections.Generic.List`1[T] newSelection, System.Int32 itemID) (at C:/buildslave/unity/build/Editor/Mono/GUI/TreeView/TreeViewController.cs:1201)
UnityEditor.IMGUI.Controls.TreeViewController.SelectionClick (UnityEditor.IMGUI.Controls.TreeViewItem itemClicked, System.Boolean keepMultiSelection) (at C:/buildslave/unity/build/Editor/Mono/GUI/TreeView/TreeViewController.cs:1190)
UnityEditor.IMGUI.Controls.TreeViewController.HandleUnusedMouseEventsForItem (UnityEngine.Rect rect, UnityEditor.IMGUI.Controls.TreeViewItem item, System.Int32 row) (at C:/buildslave/unity/build/Editor/Mono/GUI/TreeView/TreeViewController.cs:348)
UnityEditor.IMGUI.Controls.TreeViewController.DoItemGUI (UnityEditor.IMGUI.Controls.TreeViewItem item, System.Int32 row, System.Single rowWidth, System.Boolean hasFocus) (at C:/buildslave/unity/build/Editor/Mono/GUI/TreeView/TreeViewController.cs:507)
UnityEditor.IMGUI.Controls.TreeViewController.IterateVisibleItems (System.Int32 firstRow, System.Int32 numVisibleRows, System.Single rowWidth, System.Boolean hasFocus) (at C:/buildslave/unity/build/Editor/Mono/GUI/TreeView/TreeViewController.cs:691)
UnityEditor.IMGUI.Controls.TreeViewController.OnGUI (UnityEngine.Rect rect, System.Int32 keyboardControlID) (at C:/buildslave/unity/build/Editor/Mono/GUI/TreeView/TreeViewController.cs:594)
UnityEditor.IMGUI.Controls.TreeView.OnGUI (UnityEngine.Rect rect) (at C:/buildslave/unity/build/Editor/Mono/GUI/TreeView/TreeViewControl/TreeViewControl.cs:414)
UnityEditor.SettingsWindow.DrawTreeView () (at C:/buildslave/unity/build/Editor/Mono/Settings/SettingsWindow.cs:349)
UnityEngine.UIElements.IMGUIContainer.DoOnGUI (UnityEngine.Event evt, UnityEngine.Matrix4x4 parentTransform, UnityEngine.Rect clippingRect, System.Boolean isComputingLayout, UnityEngine.Rect layoutSize) (at C:/buildslave/unity/build/Modules/UIElements/IMGUIContainer.cs:298)
UnityEngine.UIElements.IMGUIContainer.HandleIMGUIEvent (UnityEngine.Event e, UnityEngine.Matrix4x4 worldTransform, UnityEngine.Rect clippingRect) (at C:/buildslave/unity/build/Modules/UIElements/IMGUIContainer.cs:483)
UnityEngine.UIElements.IMGUIContainer.HandleIMGUIEvent (UnityEngine.Event e) (at C:/buildslave/unity/build/Modules/UIElements/IMGUIContainer.cs:466)
UnityEngine.UIElements.IMGUIContainer.HandleEvent (UnityEngine.UIElements.EventBase evt) (at C:/buildslave/unity/build/Modules/UIElements/IMGUIContainer.cs:447)
UnityEngine.UIElements.EventDispatchUtilities.PropagateEvent (UnityEngine.UIElements.EventBase evt) (at C:/buildslave/unity/build/Modules/UIElements/Events/IEventDispatchingStrategy.cs:64)
UnityEngine.UIElements.MouseEventDispatchingStrategy.DispatchEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at C:/buildslave/unity/build/Modules/UIElements/Events/MouseEventDispatchingStrategy.cs:59)
UnityEngine.UIElements.EventDispatcher.ProcessEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at C:/buildslave/unity/build/Modules/UIElements/EventDispatcher.cs:280)
UnityEngine.UIElements.EventDispatcher.Dispatch (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel, UnityEngine.UIElements.DispatchMode dispatchMode) (at C:/buildslave/unity/build/Modules/UIElements/EventDispatcher.cs:156)
UnityEngine.UIElements.BaseVisualElementPanel.SendEvent (UnityEngine.UIElements.EventBase e, UnityEngine.UIElements.DispatchMode dispatchMode) (at C:/buildslave/unity/build/Modules/UIElements/Panel.cs:189)
UnityEngine.UIElements.UIElementsUtility.DoDispatch (UnityEngine.UIElements.BaseVisualElementPanel panel) (at C:/buildslave/unity/build/Modules/UIElements/UIElementsUtility.cs:255)
UnityEngine.UIElements.UIElementsUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr) (at C:/buildslave/unity/build/Modules/UIElements/UIElementsUtility.cs:78)
UnityEngine.GUIUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr) (at C:/buildslave/unity/build/Modules/IMGUI/GUIUtility.cs:179)