Unreleased outtakes, demos and BBC sessions by The Beatles from 1963 have been released on iTunes.
The 59 tracks have been released on iTunes to stop them falling out of copyright and into the public domain.
EU copyright law covers recordings for 70 years if they have had an official release or 50 years if they have not.
The 2-disc set was apparently released, then removed, early on Tuesday, causing speculation it was only being published briefly to extend the copyright period.
Fans posted screenshots of the collection on the New Zealand iTunes store, along with links which later became invalid.
Online reports suggested the same thing had happened in Australia, Russia and Saudi Arabia - although the EU's copyright laws would not apply in any of these territories.
However, the full album appeared on the UK iTunes store shortly after 14:00 GMT. The BBC has been told the songs will remain on the site "indefinitely".
Gathering together live material and recording session offcuts, the compilation includes four alternate takes of She Loves You, two of From Me To You and several live versions of Roll Over Beethoven.
It also features three attempts at There's A Place, as well as demos of two songs the group gave to other artists - Paul McCartney and John Lennon's acoustic version of Bad to Me and Lennon's piano demo of I'm in Love.
The tracks had been widely bootlegged, but never officially released until now.
After a recent change in the law, the master tape for The Beatles' 1963 debut album Please Please Me is protected by copyright until 2033, but the unreleased session tapes for that album are not.
If the Beatles chose not to release the recordings before the end of the year, other record labels could theoretically put them out and profit from them next year.
The band's 1962 debut single Love Me Do arguably slipped out of copyright last year before the EU's copyright extension was signed into law.
At least one record company issued a "remastered" version of the song, although that has since been deleted.
The copyright law in question only covers the recordings - the composition of the songs remains the copyright of the songwriter for 70 years after his or her death.
The Beatles are not the first band to issue rare material in a bid to extend copyright.
Bob Dylan's record label rushed out 100 copies of an album last year containing early TV performances, alongside multiple versions of Blowin' in the Wind, Bob Dylan's Dream and I Shall Be Free.
Officially called The 50th Anniversary Collection, it carried a subtitle which explained its true purpose: The Copyright Extension Collection, Vol. 1.
A second volume followed this year, while Motown has also begun issuing rare recordings on iTunes under the Motown Unreleased banner.