This is makeindex, version 2.15 [TeX Live 2021] (kpathsea + Thai support).
Scanning input file refman.idx..........done (6070 entries accepted, 0 rejected).
Sorting entries............................................................done (85316 comparisons).
Generating output file refman.ind.........done (7483 lines written, 0 warnings).
Output written in refman.ind.
Transcript written in refman.ilg.
