M3 Macbook Pro, Sonoma 14.3.1. Firefox ESR 115.12.0esr (64-bit). Fresh FF install right after setting up OS. Opening FF from OS opens home page. If FF is not running & I click a link in another program (email, GIMP help menu link, etc.) FF opens the linked page but ''also opens the home page (2 tabs)''. If FF is running, the linked page is opened in a new tab, leaving current tab(s) in place, the expected behavior. FF is default browser. Delete cookies and site data when Firefox is closed is selected. Created a vanilla test profile with no modifications to settings, made it default, and got the same result. On my previous laptop (don't remember FF version - whatever the latest Intel ESR version was about a month ago) opening FF from the OS opened to the home page. Opening FF (not running) from a link in another program opened '''only''' the linked page and '''not''' the linked page + home page. FF already running behaved the same as now. My OS account name is changed in the troubleshooting information.