Some features are nice, however the pop out viewer leaves MUCH to be desired.
You cannot seek, which sucks.
But the WORST part? No captions. The captions do not show in the pop out at all. This makes the video inaccessible to me. If possible, I would appreciate a fix at some point. Pop out is currently essentially useless to D/deaf/Hard of Hearing folk like me.

It's limitless if you know JavaScript

I like this add-on. Only complaint atm is that it needs audio controls to fix audio sync issues when audio doesn't quite match video. There needs to be audio timing adjustments.