Visual switches for debug flags in looking glass / lg

Opening a tracking about a feature we've been asked for a bunch of times: making shell/mutter debug flags more easily discoverable in lg.

Context: We have a bunch of debug options that are not only helpful for shell development but app/toolkit/extension developers and users as well.

Examples include damage and opaque region indicators that help app developers make their app more efficient/perform better.

Example optimized app:

Examle semi-optimized app:

Currently these debug options are not easily discoverable - the opaque region overlay above can be enabled using Meta.add_debug_paint_flag(Meta.DebugPaintFlag.OPAQUE_REGION) and so far is not well documented. Other platforms provide app devs with more easily discoverable tools. E.g. MacOS:

One easy way to archive this would be to have a section in Looking Glass that would show a list of available options, easily toggle-able, potentially with some help text. Alternatively it could be a drop-down similar to the accessibly options menu or an extension. Ideas welcome :)