Gloriosae virginis Mariae conceptum [...]

This responsory appears to be an unicum possibly in use in the diocese of Coimbra since as of Oct. '22 a search on Google of its incipit only results in a mention in the Breviarium ad usum insignis Ecclesie Eboracensis digitized at Internet Archive, p. 113 (as Manuel Pedro Ferreira and Joao Pedro d'Alvarenga have extensively shown, liturgical contents typical of Coimbra find their way in later Evora sources).
This same later Evora breviary also allows to contextualise chants for this fragment as pertaining to the feast of Conceptio Mariae.