It looks there's still no generic way to add a menu entry to all applications.
In the end, I've implemented a minimalistic filesystem (https://github.com/jollheef/appvm/blob/master/dot-desktop-fuse/main.go) that mirrors the content of original .desktop files and adds entries that I need.
Enjoy GNU/Linux on desktop 2020, lol.
@dump_stack oh wow
@cab404, may the crutches be with you.
lor.sh is yet another mastodon instance.