There are also a lot of unmerged development branches prefixed with
feature/ or
bugfix/. As implied by their names, those implement new features and bugfixes and are considered to be merged into the
master branch as soon as they're ready. Pull requests give you an overview over potential merge candidates, including those from the many SFML contributors.
So not only if you look for a specific feature not yet in
master, you might find it there -- we highly appreciate feedback to open pull requests, as that helps us improve the quality. Very valuable is the testing of the code on your own system(s), but also feedback about APIs or online code reviews are helpful.
See also:
Git Workflow