It is used to alert the maintainer(s) of a particular core subsystem that an issue significantly impacts their subsystem, and their signoff is needed (see the governance policy draft for more information). Also, if you use this tag, make sure the issue component is set to the correct subsystem.
If an issue significantly impacts more than one subsystem, use needs framework manager review instead.
⚡️ Live updates comments, jobs, and issues, tagged with #Needs subsystem maintainer review will update issues and activities on this page.