Sonora, Mexico’s Sub Pop Records-signed act Margaritas Podridas is a young group of mostly female musicians who have dipped deep into the well of a genre of early-’90s music called shoegaze. With a heavily treated and distorted guitar tone and introspective, sighing vocals, this group has mastered all the finer points of the form. Tonight they share the stage at the Miniplex with Biblioteka from Seattle, a band with a similar vibe that appears to have been very influenced by the alt-sounds from that decade (an era I only sort of remember and I am almost certain none of the group’s members were alive to experience firsthand) at 9 p.m. ($15).