Developer reply by Off JustOff
Rated 5 out of 5 stars
After updating Woterfox- doesn't work.. https://yadi.sk/d/wMTSvsXY3U7YYZ
This review is for a previous version of the add-on (2.1.0).Thank you for the report, I'm passing it to the Waterfox developer for investigation - https://github.com/MrAlex94/Waterfox/issues/512
As a workaround you can set layout.css.servo.enabled to false in about:config
To create your own collections, you must have a Mozilla Add-ons account.