Nice. On my Android it worked out Private Tab for Brave, however Firefox Focus did not get detected as such.

Not even using Chrome, except have to have it installed because lots of apps depend on it. :P

nice. can't see any difference in firefox. however, it is still possible to detect incognite mode in firefox as i have just been to a site that did so. (they didn't detect reader-mode however, so i was able to read the article after all)

For Firefox it's simple enough - can you open indexedDB? That goes the same for IE 10+. If instead it's Safari, can you successfully modify localStorage?

Unfortunately, every browser seems to change it's behaviour as soon as you try not to store your history.

Some browsers do try and stop these detection methods... And by the time they've patched them out new methods have emerged.

wait what? safari blocks access to localStorage in incognito mode? that ought to break some sites functionality.

yes that does break a lot of websites, the Safari team hasn't made the best choices on this one.