A+! They even had an iOS version a while back: `https://apps.apple.com/us/app/the-battle-for-wesnoth/id14507...` (this may be the "Mac" version, see: `https://www.reddit.com/r/wesnoth/comments/1pjkwbw/i_had_wesn...`).

If that's your jam then there's also a (non-open-source) "Hero's Hour" which tickles the old Heroes of Might and Magic stylings, works reasonably well on Xbox, where I've been doing most of my gaming lately.

As far as Open Source gaming success stories, I'd put this up there in the Top 5 for "Original IP and Concept" (if that makes sense). Just a stellar labor of love, worth giving it a shot to play!