Rogue Courser

Rogue Courser is a Minutemen radiant quest in Fallout 4.

Detailed walkthrough
This only occurs when speaking to Preston Garvey and after destroying The Institute during the main quest. The Sole Survivor is pointed in a random location, where a Courser has joined a raider gang. Wipe out the tagged foe and (optionally) any other of his raider friends. Then report back to Preston Garvey for the reward.