Как переменовать ветку на удаленном репозитории Git?

Here's how I did the renaming.

First, in your working tree, locally rename master to something else.

git branch -m master old-dev
Renaming a branch does work while you are on the branch, so there's no need to checkout something else.

Then, locally rename the maintenance branch (2.63-branch) to master:

git branch -m 2.63-branch master
Now, time to mess with the remote. Just in case you screw up, you might want to make sure you have a current backup. First, delete the remote's master:

git push origin :master
And now, give the remote your new master:

git push origin master:refs/heads/master
Update: When creating a new branch, the refs/heads/ prefix is needed on the remote side. If the branch already exists (as master did above) only the branch name is required on the remote side.

... and your now-renamed old master:

git push origin old-dev:refs/heads/old-dev
Finally, delete the old name of your maintenance branch to prevent confusion:

git push origin :2.63-branch
Clients will now get the 'new' master branch when they pull.