This is makeindex, version 2.15 [TeX Live 2019/dev] (kpathsea + Thai support).
Scanning input file main.idx....done (202 entries accepted, 0 rejected).
Sorting entries.....done (1827 comparisons).
Generating output file main.ind....done (213 lines written, 0 warnings).
Output written in main.ind.
Transcript written in main.ilg.