> Forgejo is self-hostable free software for software development, built on top of Git. Codeberg is powered by Forgejo, which is in turn a hard-fork of Gitea. Compared to Codeberg, Forgejo is not one service, but free software to help you build your own. Everyone can install their own Forgejo instance to host their own projects. There are also public Forgejo instances as well as Codeberg you can use, but make sure you find a site that is actively maintained and updated, and that you trust the provider.

Or from another angle, how would you say it more concisely? Preferably without using AI to summarise.

As a question, not a statement of knowledge, when if they'd read that “too long” paragraph they could have stated the point confidently.

And while that description, if stated as such, is more concise, it leaves out notable details (its relationshipt to Gitea, which many may recognise, and that it isn't the full feature set of the service) so is probably too concise.