wpmgr

Open-source, self-hostable WordPress fleet management: backups, updates, uptime monitoring, security, and image optimization for every site from one dashboard you own. A self-hosted MainWP and WP Remote alternative. Maintained by mosamlife on GitHub, where it has earned 78 stars from the community.

It's actively developed around backup, fleet-management, go, and is a solid reference for anyone building with these tools.