What's with git blame --reverse ?

The git blame manual page talks about using git blame --reverse to figure out when a particular change disappeared, but I cannot make it produce anything useful regardless of what range I give it. Using --root delivers a different state of uselessness.

Can anyone give a recipe for using git blame --reverse on the Git code base for figuring out anything of relevance?

Since I am in the process of rewriting git-blame, of course I want to verify that everything works, but while I achieve the same results, they seem fabulously useless before and after my rewrite.