Yes it's jQuery (and I know everyone on HN hates jQuery!) - a vanilla JS version would be just as trivial! Wrapping it in a Chrome manifest w/a simple "enable/disable" browser button-type interface would be about 20 minutes I guess.
And by the time you’ve wrapped it up, tested it, made the UI nicer (blur selected text, put a box around what will be blurred, allow for unblurring, etc.), don’t you think there’s something else you could have done for your company that would provide more than $20 value to them?
I'm in a competitive place and my company pays me to keep my sword sharp. I do that with lots and lots of solid tooling... a ton of it being stuff I've developed myself over years =)
"Don't try the blood and guts routine, let technology do the work."
Myself, I wouldn't ever put this into an extension because I'm certain it already exists and if not, I can bang out the base functionality in a console within 5 minutes and throw a gist in my GitLab or do a URL-JS thingy. 5m is worth $20 to me! $20 is a case of beers yo!