Well, especially if you take the source article to heart, "Fix" is actually future tense - "When applied this commit will fix the JS typo on foo page for Chrome". "Fixes" would indicate the present tense: "This commit fixes the JS typo [...]"

I read it as using the imperative mood, myself; otherwise the sentence is missing its subject.

I've seen that reasoning as well, but who is doing the telling, and to whom?

Ain't English fun?

If the sentence still makes sense when ", dammit!" is appended to it, it's in the imperative mood and you are the subject.

Fair enough, but how does a command apply to a git commit? If it's telling the git commit what to do, that doesn't make sense, since the commit comment is supposed to be about the commit, not a command to the commit.

If it's telling me what to do, that doesn't make any sense either, since the work's already been done; the results of doing that work is the commit.

I guess it could be considered to be an abstraction of what request initiated the change, but what value does that provide when going back through git logs (when compared to a past or present verb tense that describes the changes)?