Since version 118+, Firefox introduced FPP (Finger Printing Protection) which is in short water downed version of RFP (Resist Finger Printing).
FPP is enabled by default from version 119 onwards if you enable ETP (Enhanced Tracking Protection).
FPP randomizes canvas data subtly than RFP, which is why RFP breaks some sites. So, my question is, if we allow canvas data extraction for a broken site will it fallback to FPP's subtle canvas randomization, or allowing it will expose canvas data completely if we have ETP enabled?
Relevant link: https://support.mozilla.org/en-US/kb/firefox-protection-against-fingerprinting
Edit: More info about HTML5 canvas fingerprinting https://webbrowsertools.com/canvas-fingerprint/
https://coveryourtracks.eff.org/learn https://fingerprint.com/
RFP = I'm assuming he's referring to the about:config setting in Firefox called privacy.resistFingerprinting. This blocks fingerprinting or at least does its best.
OPP = Assuming he's referring to the other about:config setting privacy.resistFingerprinting.autoDeclineNoUserInput... It should work in coordination with the previous setting, overriding the previous restriction if you allow it.
Websites want to keep track of you without relying on cookies so they create an image with text in a canvas element, take the hash value of that and assign that as your unique id that will follow you every where you go on the internet.