Plane is open-source project tracking in the Linear mold: issues, cycles, modules and roadmaps with a fast, modern interface you can self-host or run in their cloud. The self-hosted Community Edition is genuinely capable, making it a serious option where data residency or cost rules out SaaS trackers.
It suits engineering teams that want a Linear-style tracker under their own roof. It is a younger product moving fast — expect some rough edges and a smaller integration ecosystem in exchange for control.