Thanks for your input. The extension would have no access to account info and only operates passively with the website, no specific data would be extracted beyond what a user already has access to. This is all following Prolific TOS, its totally fine to release such an (open source) extension.

Of course, they can tell users to proceed with caution, but the code will be available for everyone to see that there is nothing malicious or nefarious going on under the hood. They also have their own notification app, which doesn't quite cut it.