This PR reminds me of the changes in #274 and #312. Maybe we should use HEAD instead of main to make it more robust to future changes.

@ljharb @ctcpip I believe you have any thoughts on this. What do you think?

there are differences between them and while I prefer main for a number of reasons for most uses, like the fact that it actually results in links pointing to the tip of main rather than HEAD which will point to a specific commit id, the pattern of using HEAD has been established and it's not a hill I want to die on just yet 😄

I prefer HEAD since it will work regardless of the default branch name; the usability issue @ctcpip mentions exists, and either change is better than the wrong branch name.

Fair enough! I want to unify here whether to use HEAD or branch names. I don't think changes like main becoming the de facto standard will happen often in the future, and I just favor branch names for now. If you all have no major objections to this idea, I will make a change to switch from HEAD to branch names for remaining parts in a subsequent PR.

From my idea above, this PR looks good, at least to me. Thanks a lot! @shuuji3