“Notably the most recent version of the extension (v7.1.8) has added integrated analytics that can track all of your browsing activity across all sites.”
A popular tab extension quietly changed hands to an anonymous owner. The next update added tracking across every site you visit, and Microsoft now flags it as malware. Extensions auto-update, so users got the new owner’s code without being asked. Every extension with access to all sites is one sale away from spyware.