Differences between git pull origin master & git pull origin/master

What is the difference between git pull origin master and git pull origin/master ?

git pull origin master will pull changes from the origin remote, master branch and merge them to the local checked-out branch.

git pull origin/master will pull changes from the locally stored branch origin/master and merge that to the local checked-out branch. The origin/master branch is essentially a "cached copy" of what was last pulled from origin, which is why it's called a remote branch in git parlance. This might be somewhat confusing.

You can see what branches are available with git branch and git branch -r to see the "remote branches".

git pull origin master will fetch all the changes from the remote's master branch and will merge it into your local. We generally do not use git pull origin/master. We can do the same thing by git merge origin/master. It will merge all the changes from "cached copy" of origin's master branch into your local branch. In my case, git pull origin/master is throwing the error:

fatal: 'origin/master' does not appear to be a git repository
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

git pull = git fetch + git merge origin/branch

git pull and git pull origin branch only differ in that the latter will only "update" origin/branch and not all origin/* as git pull does.

git pull origin/branch will just not work because it's trying to do a git fetch origin/branch which is invalid.

Question related: https://stackoverflow.com/questions/61211167/git-fetch-git-merge-origin-master-vs-git-pull-origin-master/61216900#61216900