> SugarCoat is designed to be integrated into existing privacy-focused browsers like Brave, Firefox, and Tor, and browser extensions like uBlock Origin. SugarCoat is open source and is currently being integrated into the Brave browser.

Though does not mention any plans about integration with Firefox, it seems like it would be a matter of time

On firefox you're probably better off using container tabs + temporary containers. With that, you can basically have a separate browsing session (cookies/website data) per tab, which allows for isolation and doesn't require a whitelist to work (unlike the approach described in the OP).

For what it's worth:

I used Firefox (rel/dev/nightly, it varied over weeks and years) from 2011 to mid 2020.

From mid 2020, I switched to Brave as my daily driver and I won't be switching back, based on daily UX and DX.

(Brendan, thank you for getting Brave off the ground, and best of luck!)

Firefox already has Total Cookie Protection and other features like SmartBlock, which aren't exactly the same, but also work to block third party web-storage access while keeping web sites working.

It would definitely be interesting to compare and contrast the various approaches of different browsers.