The following is what mostly works (optimized or otherwise) at the moment:
DeArrow thumbnails, except for in playlists.
DeArrow titles only in video listings. The original title is still shown while playing the video.
The following is what needs to be fixed:
It cannot be configured. The only form of configuration it has is a flag for enabling/disabling DeArrow thumbnails at build time.
I am not too sure about this but I think the way it currently works breaks asynchronous requests (i.e thumbnails are fetched one-by-one rather than all at once). It also breaks YouTube's way of cancelling thumbnail requests. One of the methods I hook is a more low-level function for fetching and caching images in general and not just thumbnails, causing the problems mentioned earlier. Ideally the tweak should only hook methods specifically responsible for thumbnails and video cells.
Video titles during playback are not replaced with DeArrow versions.
Titles in video cells are not resized or restyled to make space for some of the longer DeArrow titles.
The tweak allows you to view the original video title by pressing on the title. This could be somewhat annoying/confusing from a UX perspective.
The code is very unstructured/messy. There's a lot of duplication and dead code from earlier tests.
Titles for video cells in playlists reload everytime they appear/disappear and if I remember correctly they don't use DeArrow thumbnails.
Just wondering what needs to be finished for this to be a complete tweak.