Rev-10's Mission refers to Rev-10 being sent to 1995 by Dani Ramos to protect John and Sarah Connor as well as "Uncle Bob" while also trying to prevent the creation of Legion.
Due to the events of Terminator: Dark Fate - the timeline changed significantly as Dani decided to repay Sarah Connor the favour for protecting her by sending a reprogrammed Rev-10.
The Rev-10 series was being developed by Legion in 2044, however, the resistance managed to trick Legion into using a code they created which in turn caused all Rev-10's to be reprogrammed as members of Resistance.
Must Rev-10s were converted from regular humans, however, "Emily" was converted from the outer sheath of a female Rev-9 making her unique as well as gaining a few unique traits known to Rev-9s.
The Battle Edit
"Emily" arrived at the heart of the events pertaining to Cyberdyne and quickly mimicked a cop uniform and stole the T-1000's motorcycle and gave chase while "Rev" arrived before the attack on Cyberdyne and "Clerk" arrived just a few hours after Sarah, John, and "Uncle Bob" left Enrique's compound.
Due to actions of Rev-10; "Emily's" timeline no longer exists and thus the events of Terminator: Dark Fate was erased.