Hi,

The people who answer questions here, for the most part, are other users volunteering their time (like me), not Mozilla employees or developers. If you want to leave feedback for developers, you can go to the Firefox Help menu and select Share ideas and feedback…. Alternatively, you can use this link. Your feedback gets collected by a team of people who read it and gather data about the most common issues.

You can also file a bug report or feature request. See File a bug report or feature request for Mozilla products for details.

Picture-in-Picture should support BBC subtitles since Firefox 103.

Are they still missing in a new profile? An easy way to test a new profile is to install Developer Edition and see if it happens there or refresh your existing profile.