Currently the options for Branch Permissions are:
Prevent all changes
Prevent rewriting history
Prevent changes without a pull request
There is currently no way to allow developers to commit to branches but prevent them from creating new ones n a repository.
This can be a problem when a structured set of branches is desired (eg versioned releases) for developers to write to, but control over who creates them and when is desirable. In particular, unprotected branch creation can lead to developers inadvertently inserting their release branch into a cascading merge chain.
Implement separate "Prevent Create", "Prevent Modify" to replace "Prevent all changes". This would allow administrators to control creation of branches, while letting developers commit to them