The AUTHORS files indicates the list of people with commit access right who can actually merge the patches.
The general rule for committing a patch is to make sure it has been reviewed properly in the mailing-list first, usually if a couple of people gave an ACK or +1 to a patch and nobody raised an objection on the list it should be good to go. If the patch touches a part of the code where you're not the main maintainer, or where you do not have a very clear idea of how things work, it's better to wait for a more authoritative feedback though. Before committing, please also rebuild locally, run 'ninja test', and make sure you don't raise errors.
An exception to 'review and approval on the list first' is fixing failures to build:
if a recently committed patch breaks compilation on a platform or for a given driver, then it's fine to commit a minimal fix directly without getting the review feedback first
if ninja test breaks, if there is an obvious fix, it's fine to commit immediately. The patch should still be sent to the list (or tell what the fix was if trivial), and 'ninja test' should pass too, before committing anything
fixes for documentation and code comments can be managed in the same way, but still make sure they get reviewed if non-trivial.
(ir)regular pulls from other repositories or automated updates, such as the keycodemap submodule updates, pulling in new translations or updating the container images for the CI system