The term "repack" typically refers to a re-packaged version of a game that has been modified to reduce its file size or to bypass certain digital rights management (DRM) protections. Repacks are often created by enthusiasts or groups that aim to make games more accessible to players with slower internet connections or those who want to play the game without the need for a specific DRM.
Wait, the user wrote all the keywords together without spaces. Maybe that's intentional. Let me break it down again: batmanarkhamknightfrenchmephisto_fitgirl reack link. Breaking it into possible parts: BatmanArkhamKnight is the game title. French Mephisto could be a region or a mod name. Fitgirl is the repacker. So the user is looking for a repack of Batman: Arkham Knight for the French MEPHISTO edition by Fitgirl.