This is makeindex, version 2.15 [MiKTeX 21.6.28].
Scanning input file GradualeMonasterienseParsSecunda-Hymn.idx....done (5 entries accepted, 0 rejected).
Sorting entries....done (15 comparisons).
Generating output file GradualeMonasterienseParsSecunda-Hymn.ind....done (18 lines written, 0 warnings).
Output written in GradualeMonasterienseParsSecunda-Hymn.ind.
Transcript written in GradualeMonasterienseParsSecunda-Hymn.ilg.