https://github.com/overviewer/Minecraft-Overviewer
QuotePLEASE NOTE: Overviewer is currently unmaintained. PRs will not be merged and issues will not be addressed. The website and repository will remain online and accessible.
It will still work unless a major change happens to the map file format but that could happen soon.
If anyone knows of some alternatives or forks I should check out, let me know.
Oh man!
That makes me Big Sad :(
Did a little research these appear to be alive, may need more research, some need an alternative server.
https://github.com/tectonicus/tectonicus
https://github.com/jpenilla/squaremap
https://bluemap.bluecolored.de/
https://github.com/webbukkit/dynmap
https://modrinth.com/plugin/pl3xmap
Bluemap looks pretty cool, but for just a map, I prefer the style of Tectonicus.