[lucideer]

It seems odd at first until you realise that it's a host setting & a convention, rather than an inherent limitation.

The familiar model of "centralised" Git hosts like Github come bundled with their own protocol-specific permissions models. E.g. if you were to imagine a team working from a simple .git directory hosted on a local SMB/whatever LAN share, the permissions model would be file permissions on the networked filesystem.

Blocking users committing to an "owned" branch on SSB would require implementing an ACL-tracking & ownership model attached to namespaces (likely branch prefixes here by convention) - very doable, nothing about the protocol prohibits it architecturally. So if it ever becomes one of those "good problems", it's not an inherently concrete design decision.