According to an explosion of articles on this extension: (one from robertheatonDOTcom) "since January 2017, Stylish has been augmented with bonus spyware that records every single website ... its 2 million other users visit"

Let that sink in... Every. Single. Website. Recorded and Saved.

My understanding was that they were removed from both Mozilla and Chrome stores. Shocked to see them back here after the base betrayal of their userbase. Shame on Mozilla for allowing this. This should be a lifetime ban!

Use STYLUS (github) instead. Use this extension at your own risk. (forewarned in forearmed)

The review below mine made by @riversiderepeat says is true to an extent -- Stylish is indeed a spyware, but Stylus IS NOT. They (the user that made the comment) clearly put 0 (as in none) effort into researching the add-on, looking at the source code, reading the wiki page, or really just looking at forum posts and/or articles all over the web about Stylus and why it exists -- which is very ignorant on their end.

What Stylish is doing here is very malicious and to see it being brought back to AMO is a disgrace. Mozilla, is this the way you fight for the privacy of your users -- by letting some 3rd party companies steal the data of your users?

By bringing back the add-on to the AMO with all the spyware inside of it, which is just one single click away and people get NO warnings about the seriousness of the data they're going to be giving out for a feature that's used once in a while and never again, is seriously disappointing. Sigh.

To Stylish developers, shame on you guys and congratulations on destroying one of the most amazing add-ons that were ever created as well as the USo, the forum, and everything in between. The add-on became a disappointment once it was sold out the first, and especially even more so when it got sold the second time.

Since a better addon "Stylus" exists, this legacy "Stylish" version is only giving away your complete browsing history to a commercial and dubious 3rd party in exchange for sweets.

At first sight, it might conform to Mozilla's "no surprises" policy as the little cartoon doggie clearly begs for all urls. But it's not necessary, and the comfy link to userstyles is obviously just for grabbing your privcate data. Proof ist that there seems to be no way to manually check only for sites you actually would like a style for.

A lot of users will still use it because it's a well-known name and has been reviewed a lot in the good ol' days. Mozilla has a real problem with addons changing their policy for the worse. Avoid at all costs and use the alternative addon Stylus.