Not sure about Gitea, but Forgejo is what is being used for Codeberg (and maintained by the same people, maybe?) whereas the voluntary association behind Codeberg (Codeberg e.V.) has at least 429 members (https://blog.codeberg.org/letter-from-codeberg-looking-into-...), so I think it's pretty safe to say Forgejo will be maintained for the time being.
How many of those members are actually capable of maintaining the codebase? How many of them will leave at the first sign of trouble or some petty conflict?
I'm guessing most of them, as the organization is focused around codeberg.org, a git repository hosting service, like GitHub but open source and supported by a non-profit.
It'd be pretty weird for non-software developers to join a non-profit association behind a git forge. And if that wasn't enough, joining the association also requires paying an annual fee.
If the existing leadership disappeared tomorrow though, how many would actually have enough free time and energy to actually continue running the ship? That I'm not sure about, but the capability is there if there is will.
Politically-motivated forks by non-developers have happened in the fast. For example, https://github.com/ayojs/ayo — a fork of node.js, whose only changes were to README.md and CODE_OF_CONDUCT.md, everything else was just copied from Node.
> Politically-motivated forks by non-developers have happened in the fast
Sure, but is that really what Codeberg/Forgejo is? As far as I can tell, the contributors have demonstrated they have technical capability (look at Woodpecker or Codeberg.org itself for examples), so they're not non-developers.
And the fork happened as a way for them to protect codeberg.org, as the main software they were using for codeberg.org seemed to have volatile ownership, so it's a move to avoid any potential issues, not just a "politically-motivated fork", but a "organization survival fork".
As a counter-example, look at iojs, which was also a fork of nodejs, because of disagreement of governance. Eventually, nodejs conceded and eventually the two projects were re-merged with each other, with changes from iojs being accepted into nodejs.
gimp fork glipse is even funnier as an example