If you're updating or maintaining #flatpak on #flathub, you might want to check out this script I made. It does a few things like set the flags that flathub uses, checks for 128x128 icons, checks if your appstream is good and if your desktop file has the right appid. It'll likely avoid you a couple of "ah crap, it failed on flathub but works locally". It's also generally good practice. Improvements more than welcome!
Fosstodon is an English speaking Mastodon instance that is open to anyone who is interested in technology; particularly free & open source software.