Yes, the YouTube video shouldn’t say “Front Differential”! The fluid he’s changing is “Front Transfer Case” gear lubricant!
For CX-5 and most CUV’s FWD, the front differential is within automatic transmission box and uses the ATF for lubrication. People also call it “transaxle” for the whole unit. For AWD a seperate front transfer case is piggybacked to the transmission or transaxle transferring power to the rear differential via a drive shaft. Front transfer case uses gear lubricant as it’s an independent unit and gear lub apparently is better suitable for all the gears inside. This design is also easier for car manufacture changing FWD configuration to AWD. I guess that’s why sometimes even dealers are getting confused!