Browser Add-On Stylish for Chrome/Firefox banned

[German]Google and Mozilla have banned the Stylish browser extension (AddOn) from the stores. Here is some background information about this add-on.


Browser Add-On Stylish

The quite popular browser add-on Stylish was available for browsers like Google Chrome, Firefox, Opera and Safari. The add-on is available in the Google Chrome App Store, for example, and has over 1.5 million users there.


According to advertising, the Stylish add-on was a user style manager that can be used to redesign the web. Stylish makes it easy to define themes and skins for many websites. The browser extension became a hit because it allows users to place their own overlays on websites and hide features they don't want to see.

My warning from January 2017

The AddOn was sold to a new owner (Justin Hindma) in October 2016. Already in January 2017 I had the article Browser Add-On Stylish – der neue Datensammler? within my German blog. There I warned against this add-on, because it extracts the user's data. My advice was to stay away from this add-on.

Google and Mozilla finally banned that add-on

Now I read at that Google and Mozilla finally removed tha add-on from the Mozilla repository and Chrome App Store. Background to the ban is, that the popular Stylish extension collects data about website visits in a way that could be used to identify users.


The provider writes in his Stylish Privacy Policy that the data collected does not allow any conclusions to be drawn about the user. But this seems to be not true, as software engineer Robert Heaton's research has shown. Robert Heaton described the demise of the add-on from a useful tool that he had used for several years to today's data collector with threat to privacy. Within the article it is mentioned, that the Chrome version of this add-on has been tracking since January 2017 (matches my blog entry above). The Firefox add-on has integrated the tracker since March 2018. Robert Heaton describes in great detail what the add-on transmits. Not only are URLs logged, but each data record is assigned a user-specific ID. The user can be identified by this ID and the information collected.

Mozilla has removed Stylish from its Firefox add-ons catalog. "We have decided to block for violating the data practices described in the review policy," wrote Mozilla software developer Andreas Wagner. The Stylish page in the Chrome Web Store now displays a 404 error page. If someone is using this add-on, I recommend to uninstall it immediately.

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