It’s a tribute - 60s covers of various iconic Summer of Love songs by the so called Paisley Underground bands (Three O’Clock, Bangles, Rain Parade, Dream Syndicate, etc) back in 1984.
Rainy Day mastermind David Roback eventually went on to form Mazzy Star and is the visionary behind this whole concept. I wrote a lengthy feature about the whole Paisley scene for Magnet many moons ago but it still stands up pretty well:
https://magnetmagazine.com/2001/05/18/one-nation-underground-the-story-of-the-paisley-underground/