I'm trying out a 'claim to be Chrome or Firefox but don't have a Sec-Fetch-Mode header, you lose' filter on my techblog, but one immediate discovery is that Googlebot doesn't send Sec-Fetch-Mode even when its UA has 'Chrome/<some version>' in it.
This trick comes from: https://come-from.mad-scientist.club/@algernon/statuses/01KA7ADJ7XPXFYSZA2W7ST81ZS
