Love the concept! It makes adding progress to DS an absolute breeze.
Only reason for the 4 stars is the inability to use the extension on embedded youtube videos, which prevents it being as useful in conjunction with sites like Comprensi (which is another genius addition to the DS experience). Would it be possible to add support for Comprensi and/or YouTube front-ends like Piped/Invidious?
Also is there somewhere I can donate as a thank you?