Changes in Thunderbird 102.3.3
default_windowsmanifest key to browserAction, allowing to show the action button also in stand-alone message windows.
tabparameter to the onCommand event, returning the currently active tab. Since the event is a user input event handler, it was not possible to query the active tab (via browser.tabs.query()), without loosing this elevated status due to calling an asynchronous function. Solved by returning the tab as a parameter (similar to onClicked and other user input event handlers).
Bugzilla list of fixed WebExtension API defects uplifted from Thunderbird 106.