With this extension you can visually mark and remember your favorite tamistamps of any video on YouTube and quickly navigate between them.
The extension adds customizable visual markers to the progress bar of the video and allows you to quickly navigate between them. Also it has a viewable history of marked videos. Additionally, the extension allows you to create screenshots with one click on hotkey and removes some annoying popups.
This extension does not collects your data. You can find all source code here
https://github.com/StasPlatonov/youtube-timestamp-storage