AF (arkenfox) vs LW (librewolf)
AF enables SB (safe browsing) and uses mozilla's API key. LW doesn't have a SB key (edit: note AF does block real time binary checks)
AF updates same as Firefox. LW has no updater in windows
AF can use any language, LW is limited to en-US
AF restricts cross-site referrers by default
LW ships with uBO - AF users have to do that manually and add/flip the two recommended filters as per the AF wiki
So basically everything you see at Arthur's independent test site at https://privacytests.org/ for LW applies to AF along with referrers (navigational) with a green check as well