This is makeindex, version 2.17 [TeX Live 2025] (kpathsea + Thai support).
Scanning input file refman.idx.........done (5646 entries accepted, 0 rejected).
Sorting entries......................................................done (75913 comparisons).
Generating output file refman.ind.........done (9095 lines written, 0 warnings).
Output written in refman.ind.
Transcript written in refman.ilg.