Does anyone know what are ISRCs starting with ‘X’ or ‘Y’ (e.g, Y72800008715)? SoundExchange is full of them, but MusicBrainz considers them invalid. I understand that an ISRC must begin with a country code, which those are not. What are they then?
Where are you seeing them? When I try to look up your example at https://isrc.soundexchange.com/ it just tells me “server error”…
The ISRC Handbook doesn’t mention them, AFAICT.
From what I can gather X in general means user-assigned while Y means unassigned. I’m curious to know the answer to this too!
According to Wikipedia, XA through XZ is available for user-assigned country codes (which is why MB has things like XE fir Europe). Yx is not shown as valid in any way. Even if it was, an alpha-2 code can only have letters (avoiding collating sequence issues), so Y7 can never be a valid prefix for an ISRC.