I use source control religiously in my development. I would never think of writing code without saving it in a source control system and checking in "early and often".
So why was I hand-editing the template for my blog without first saving the old version? Misplaced confidence, that's why. Of course I made one too many changes and completely screwed it up.
Since I had no source, I had to rebuild it from another blog's template. It is now under source control.
This is a lesson I learned many years ago. I just keep learning it over and over.