Calling your album Star Wars, sticking a picture of a cute cat on the cover, and naming songs things such as Random Name Generator might whiff of a band’s late-life internet malaise. Not so this free album by Wilco, one of the giants of American guitar music, stealth-released a few days ago in their 20th-anniversary year. “I’m not missing what I’m giving away,” sings Jeff Tweedy on You Satellite, just one of 11 songs that strike the right attitude between experimentation and tunefulness. Looser, grungier, fuzzier and yet more abrupt, perhaps, than latter-day Wilco offerings, Star Wars is proof that you can get considerably more than you pay for.