Video Time Manager от Avi

The extension shows you where your YouTube time actually goes

What you get
- Watch-time breakdowns, clear and simple
- Works on YouTube and YouTube Music
- Everything stays on your device by default, with an optional backup to your own Google Drive - nothing sneaks out anywhere else

Why it matters
- Your YouTube watch patterns say a lot about you - this is a fun way to actually see them

There's also VidMatch built in, which matches you with people who watch similar stuff to you about your watch time.