Several official examples are provided to demonstrate the usage of Addons. Addons are placed in the UserPrefs/Addons/ folder as a set of folders and subfolders. You may add .py and .cpp files there. Each file appears in the tree of the Addons submenu. If the name of a file or folder starts with a . or _, it will not appear in the tree. The txt files also appear as menu items; this readme.txt is an example. If a file has the .url extension, it opens as a URL in the browser. If a txt file contains a URL, such as https://pilgway.com/files/3dcoat/PythonAPI/index.html, an "Open URL" button appears below the dialog.