Firefox history contains youtube videos I didn't watch (and that aren't in my google youtube history). I've realised they go back May, roughly when I got my new linux machine and installed Firefox. However, they also seem to have been watched outside the time any of my devices apart from my phone are on. They're mostly just junk videos about minecraft etc. See attached pic - the ones this morning between 5.48 and 7am I didn't have the laptop turned on. My phone was on though, but by the bed. How has this happened and how can I track down how to stop it? I'm writing this on my Windows desktop, can send details of other devices if useful.