This box set was released June 5, 2020 by PopMarket ($128.79), MusicGlue ($160.00,) and Amazon ($193.99). As part of the promotion, MusicGlue released a cool box set promo video that you can watch on YouTube.

Here's a little more information from MusicGlue about the box set:

The year 2020 marks the 50th Anniversary of perennial classic-rock favorite, America. America Records is proud to release the ultimate 8-disc Anniversary Box Set. Produced for release and compiled by Jeff Larson for America Archives. Containing CDs of rare archival studio recordings consisting of alternate mixes, demos, and rehearsals, including several previously unreleased tracks ranging from 1970 - 2000. Along with the re-mastered Bremen 1973 in-studio performance and two CDs of Radio Interviews providing an audio overview of the band's career, along with a DVD of Super 8 'Home Movies' (1972-1975) to give fans a behind the scenes look at the early years of this enduring band.

Disc 1: London Demos 1970: All Previously Unreleased
These early demos from the Fall of 1970 represent America - The Trio recording songs that preceded their debut album for Warner Bros. Records. Gathered here, is the most complete collection to date of demos from this era recorded at three iconic London studios of the time.

Disc 2: Bremen 1973: (Only previously available as a DVD)
An on-air live recording of the Trio from 1973, in-between the albums Hat Trick and Holiday. This recording has been remastered for the first time and includes all the un-edited studio banter.

Disc 3: The Caribou Sessions 1976 - All Previously Unreleased
A collection of demos, rehearsals and outtakes towards the recording of America's 6th studio album, Hideaway in February 1976. The early takes and rehearsals stem from the famed Caribou Ranch Studios in Nederland, Colorado. Both the original home demos and session outtakes here provide a glimpse into the recording process before the later overdubs and strings were applied.

Disc 4: The Poison Oak Sessions 1981: All Previously Unreleased
In 1981, between the album Alibi (1980) and View From The Ground (1982), the band recorded several songs at Dewey's home studio, Poison Oak, in Northern California. This set contains early incarnations and alternate versions of songs released on later America albums as well as new songs that have been in the vault until now.

Disc 5: The Alternate 90's Plus: All Previously Unreleased
Alternate mixes from The albums Hourglass (1994) and Human Nature (1998) along with unreleased songs that came before, in-between and after these official releases. This set also closes with a new 2020 recording with the song "Remembering".

Discs 6 & 7 America on the Radio - All Previously Unreleased
Various radio interviews stemming from 1974 - 2000's which provide's a narrative and unique overview to their long career.

Disc 8 America - Home Movies (DVD) - All Previously Unreleased
This collection is very, "fly on the wall" footage. These films provide an amazing insight into the band, shot between 1972 and 1975, showing behind the scenes footage of, "Hat Trick at Home", early attempts at making home making of music videos and various on the road activities. These films give the viewer an amazing view of historical events as they unfolded.