I wonder how much of that is from Linkedin checking what browser extensions you have, probably desperately trying to prevent screen scraping?

https://news.ycombinator.com/item?id=46904361

That code is minimal. It’s definitely not the source.

Given all the sales and recruiting spam I get, I think it’s a good thing that LinkedIn is making efforts to detect people using garbage plugins that scrape data and send it to their servers or prepare it for mass spamming.