To be specific, my goal is to have access to this specific commit https://github.com/ankidroid/Anki-Android/commit/73afde67830bb6e49388d0e3a135e945fdbbfc4a

The issue is that the commit is outside a specific branch. So I can't just fetch its branch. git fetch ankidroid 73afde6 (where ankidroid is my local name for this remote) or git pull ankidroid 73afde6 fails. If I do git fetch the command at least succeed, but the commit 73afde6 is still not known.

CodePudding user response：

Some hosting sites won't allow you to fetch a commit by its hash ID. If you are using such a hosting site, you must find some name that will allow fetching the commit. Fortunately for you, you are using github, which does allow fetching by raw hash ID.¹

The trick is that you must use the full hash ID. That is, run:

git fetch ankidroid 73afde67830bb6e49388d0e3a135e945fdbbfc4a

The command:

git fetch ankidroid 73afde6

does not suffice.

(You might want to give the commit a name you can refer to in your local repository, e.g., git fetch ankidroid 73afde67830bb6e49388d0e3a135e945fdbbfc4a:refs/heads/foo. This creates a new branch name foo in your local repository, pointing to the fetched commit. This assumes you do not currently have a branch named foo; if so, substitute in some other name.)

¹The new partial clone feature requires this, so it's becoming more common.