Developer reply by Oleksandr
Rated 5 out of 5 stars
Please update this. :)
This review is for a previous version of the add-on (5.10).Unfortunately, WebExtensions (the new API for Firefox 57+) does not have the functionality for the correct operation of this addon in Firefox.
But you can install Firefox 52 ESR and enjoy work until June 2018
https://www.mozilla.org/en-US/firefox/organizations/faq/
To create your own collections, you must have a Mozilla Add-ons account.