Stylish is/was a very popular extension for the Chrome and Firefox web browsers, which let users add custom styles to certain websites. I was using it myself, until a helpful fellow told me it was apparently spyware; new owners decided to engage in data-slurping activities, which caused Google and Mozilla to pull the plugin from their stores.
However, since it's back in store, does that mean they've removed the malicious part of the code and it's safe to use again? I'm not really opposed against general data statistics gathering, I just don't like being uniquely identifiable.
We do not want to know your identity or any other personal information and we do not automatically collect data to try and figure out who you are
but stating is one thing, actually doing it is another.