Question: What former member of the country group Uncle Tupelo contributed to the album Down in a Mirror: A Second Tribute to Jandek?
Context: Jeffrey Scot Tweedy (born August 25, 1967) is an American songwriter, musician, and record producer best known as the singer and guitarist of the band Wilco.  Tweedy, originally from Belleville, Illinois, started his music career in high school in his band The Plebes with Jay Farrar, which subsequently after several years formed into the alternative country band Uncle Tupelo.  After Uncle Tupelo's fourth studio album, the band broke up in 1994 due to conflict between Tweedy and Farrar, prompting Tweedy to form Wilco, with Farrar forming the band Son Volt.  Wilco's first album "A.M.", released in 1995, received mixed reviews from critics, though Wilco later found critical and commercial success on their later albums, most notably with "Yankee Hotel Foxtrot" and "A Ghost Is Born", the latter of which received a Grammy for Best Alternative Album in 2005.  Across Tweedy's career he has released fifteen studio albums, including four with Uncle Tupelo, ten with Wilco, and one with his son Spencer, along with numerous collaborations with other musicians, most notably "Mermaid Avenue" with Billy Bragg. Bulldog gravy was a Great Depression-era foodstuff associated with American coal miners.  It was a mixture of water, flour and grease, and eaten with beans or over a "water sandwich" (bread soaked in lard and water).  It is mentioned in the lyrics of the Appalachian lament "Man of Constant Sorrow" (or "Girl of Constant Sorrow", depending on the performer.)  It is also mentioned in the lyrics of Sarah Ogan's "Come All You Coal Miners," covered with the title shortened to "Coalminers" by the alt-country group Uncle Tupelo, on their album, "March 16-20, 1992." Down in a Mirror: A Second Tribute to Jandek is a tribute album compiled by Moscow, PA-based independent record label Summersteps Records, released as a follow-up to the label's first Jandek tribute, "".  As with "Naked in the Afternoon", "Down In A Mirror" features cover versions of songs by the reclusive avant-folk/blues singer/songwriter Jandek.  Some of the artists are members of the Summersteps roster or fans forming one-time combos to participate on the album, but the album also features contributions from Wilco's Jeff Tweedy, Six Organs of Admittance (reportedly a favorite modern act of Jandek's, according to the "unauthorized" "Texas Monthly" interview), The Mountain Goats, Kawabata Makoto of Acid Mothers Temple, Lewis & Clarke and Okkervil River. Wilco is an American alternative rock band based in Chicago, Illinois.  The band was formed in 1994 by the remaining members of alternative country group Uncle Tupelo following singer Jay Farrar's departure.  Wilco's lineup changed frequently during its first decade, with only singer Jeff Tweedy and bassist John Stirratt remaining from the original incarnation.  Since early 2004, the lineup has been unchanged, consisting of Tweedy, Stirratt, guitarist Nels Cline, multi-instrumentalist Pat Sansone, keyboard player Mikael Jorgensen, and drummer Glenn Kotche.  Wilco has released ten studio albums, a live double album, and four collaborations: three with Billy Bragg and one with The Minus 5. Wilco: Learning How to Die (2004, ISBN  ) is a book by "Chicago Tribune" rock critic Greg Kot.  The book was written with the cooperation of Wilco band members past and present.  It covers the time period from when Wilco singer Jeff Tweedy was born, through the formation and breakup of Uncle Tupelo, and the career of Wilco through their 2004 album "A Ghost Is Born".  It is primarily written as an oral history, featuring interviews with Tweedy, John Stirratt, and other Wilco members, as well as manager Tony Margherita and Uncle Tupelo drummer Mike Heidorn.  The book's title comes from a lyric of Wilco's "War on War", which appears on their 2002 album "Yankee Hotel Foxtrot".  It was published on June 15, 2004 by Broadway Books.  The book received positive reviews from outlets such as "The New York Times". Anodyne is the fourth and final studio album by alternative country band Uncle Tupelo, released on October 5, 1993.  The recording of the album was preceded by the departure of the original drummer Mike Heidorn and the addition of three new band members: bassist John Stirratt, drummer Ken Coomer, and multi-instrumentalist Max Johnston.  The band signed with Sire Records shortly before recording the album; "Anodyne" was Uncle Tupelo's only major label release until "" in 2002. A.M. is the debut studio album by the American alternative rock band Wilco, released on March 28, 1995, by Sire Records and Reprise Records.  The album was released only months after the breakup of Uncle Tupelo, an alternative country band that was the predecessor of Wilco.  Prior to its release, there was debate about whether the album would be better than the debut album of Son Volt, the new band of former Uncle Tupelo lead singer Jay Farrar. Mike Heidorn, born 1967 in Belleville, Illinois, is the former drummer and founding member of alternative country bands Uncle Tupelo and Son Volt.  Heidorn also played with the Uncle Tupelo precursors the Primitives (or Primatives ) and the one-off band Coffee Creek with Jay Farrar and Jeff Tweedy of Uncle Tupelo and Brian Henneman of The Bottle Rockets.  Heidorn married and left Uncle Tupelo after the recording of their third album, March 16–20, 1992.  After the breakup of Uncle Tupelo Heidorn was reactivated by Farrar and joined the first version of Son Volt, but was not involved in the reformation of the band in 2005 and is no longer active as a professional musician. Uncle Tupelo was an alternative country music group from Belleville, Illinois, active between 1987 and 1994.  Jay Farrar, Jeff Tweedy, and Mike Heidorn formed the band after the lead singer of their previous band, The Primitives, left to attend college.  The trio recorded three albums for Rockville Records, before signing with Sire Records and expanding to a five-piece.  Shortly after the release of the band's major label debut album "Anodyne", Farrar announced his decision to leave the band due to a soured relationship with his co-songwriter Tweedy.  Uncle Tupelo split on May 1, 1994, after completing a farewell tour.  Following the breakup, Farrar formed Son Volt with Heidorn, while the remaining members continued as Wilco. No Depression is the first studio album by alternative country band Uncle Tupelo, released in June 1990.  After its formation in the late 1980s, Uncle Tupelo recorded the "Not Forever, Just for Now" demo tape, which received a positive review by the "College Media Journal" in 1989.  The review led to the band's signing with what would become Rockville Records later that year.  The album was recorded with producers Sean Slade and Paul Q. Kolderie at Fort Apache Studios, on a budget of US$3,500.
Answer: Jeff Tweedy