I’m a software developer, but that doesn’t mean that it’s super easy anyway. For one I’m not familiar with WoW Addons. I can pretty easily pick up LUA, but I’m also unfamiliar with the WoW Addon API, and also how whoever coded it coded it…
It’s very unlikely something that I could just figure out in say 5-10 hours. But, given a few days of full-time work, probably. And that’s if it’s as simple as finding some commit points in the code history where it’s a functional addon that just needs some updating to work on the modern client.