The "clapper_src" directory name was unusual. This was done to make it work as a widget for other apps. Now that this functionality got removed it can be named simply "src" as recommended by guidelines.
This seemed like a good idea when the app still used GTK3, but GTK4 already has a built-in video widget. Maintaning this single functionality would be hard and I cannot promise a stable API anyway. The app main and only purpose will be a video player from now on.
Default "GLib.log_structured" method is painfully slow and time provided by it is not very accurate. It also slows down program execution even when G_MESSAGES_DEBUG env is not set. Use custom debug scripts for faster and more accurate messages logging instead.