Firstly, thank you for a detailed review. The other extension's main goal seems to be to save bookmarks for the user, whereas mine saves them primarily for itself, so that it can act upon them when a video is loaded. (It automatically seeks to those "interesting segments" of a video which is playing potentially as part of a playlist, thus simulating a playlist of partial videos).

In principle it makes sense to extend this feature to all HTML5 videos. However I'm not sure how diverse the logic of detecting the video load will be across websites, which are increasingly using SPA. But I still like this idea. In my free time I do want to survey the effort required to achieve it. Thanks a lot for the suggestion!