Local or remote branch?

[raffaem]

In this URL there is written that this command:

git pull upstream master --ff-only

pull the changes from the remote known as upstream into the master branch of my local repo

But I think in that command master is the branch of the remote upstream, not the branch of the local repo?

I think the branch of the local repo is just the checked out one?

In the git documentation for example there is written that:

git pull origin next

means

Merge into the current branch the remote branch next

So next is the remote branch