The tags are useless. It's possible that the chants were collected for Spain and that it comes from a Liber Usualis or similar book published with a proper Mass.
I don't know how to contact the original user and "Verbum Gloriae" who apparently has a copy in front of him or her.
I do believe there is an extensive library of manuscripts in Campostella…. I seem to recall seeing a short documentary about chant that showed some of the manuscripts there. Perhaps there is a diocesan archivist you could email.
I (Verbum Gloriae) scanned both Spanish supplements and uploaded them to my Spanish website of apostolate of Gregorian Chant: https://www.verbumgloriae.es/recursos/libros/#seccion4 -----------------------------------------------
OK now I got it, my mind has connected the neurons between the GregoBase user "Verbum Gloriae" and his YouTube channel. This young man publishes good recordings of Gregorian chant and he's got a lovely melodic voice: https://www.youtube.com/c/VerbumGloriae/videos
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