Editors continue to use publicly available scripting tools to seed fake digital release dates (and other mismapped data like like release labels) to MusicBrainz without critical thought.

https://musicbrainz.org/report/ReleasedTooEarly theoretically covers these, but does not actually, per https://musicbrainz.org/search?query=format%3A%22Digital+Media%22+AND+date%3A%5B1900+TO+1998%5D&type=release&limit=100&method=advanced (1,692 vs 11,838)

1999 is an extremely generous start date for digital media releases [1], but realistically, the vast majority of digital media releases in MusicBrainz with dates prior to 2003 are also fake dates. (Furthermore, many digital release dates after 2003 are also fake, but those are harder to filter for.)

[1] At minimum, anything with a date prior to 1993 is fake data, anything with a date prior to 1999 is almost assuredly "indie" releases or unauthorized, rather than something from major labels - https://en.wikipedia.org/wiki/Digital_music_store#Early_years