"Mariachi De Amigos" is an instrumental track composed by Donald Quan and Rick Lazar.
It is featured in the Fallout TV series episode "The End", playing in the background when the bounty hunters take out one of Dom Pedro's guards.
On Amazon Prime, only the APM Music company that the track was licensed from was credited for it. It was previously also featured in "The Diviner", an episode of Fear of the Walking Dead.