Let's look a bit closer at this regex.  We don't need capturing parentheses here, the non-greedy `+` isn't necessary, and I'd need to double-check, but let's look at if there's any risk related to `$` vs. `\z` here.

I would at least go with:  `/.\.zep\.(?:c|h|php)$/` and possibly `.\.zep\.(?:c|h|php)\z` (though I'm guessing we're actually alright with `$` here).