According to this:
https://www.bleepingcomputer.com/news/software/2-million-users-impacted-by-new-data-collection-policy-in-stylish-browser-add-on/
https://robertheaton.com/2018/07/02/stylish-browser-extension-steals-your-internet-history/
https://www.ghacks.net/2017/05/16/stylus-is-a-stylish-fork-without-analytics/

this plugin tracks your internet traffic. This cannot be tolerated