LinkedIn is far from the only actor doing this. Browser extension fingerprinting is not new. LinkedIn‘s size, scope, network effects make this especially concerning.

Still pretty annoying browsers haven't patched that yet.

This has been going on for at least 5 years. It pops up on HN every so often.

Seems like it. Which is serious but far from what I thought when I read the title. I suspect 90% of LinkedIn users don't even have a single browser extension installed.

Pretty sure that if they could they would, but browsers sandboxing security prevent this to go unnoticed.