“Tool Menus” are what Unreal calls most of the menus in the editor. These are almost all extensible via code.
The two main classes related to this are UToolMenus, which is used to access different menus, and UToolMenu which is an instance of a menu.
How to find the UToolMenu name
To add custom entries to a menu (such as for Customizing the New Asset menu with Slate), you need to know the name of the menu.
- Run the console command
ToolMenus.Edit - This adds an entry into each menu where you can either immediately see the name of the menu, or you can click an edit icon to see the name of the menu.