This is makeindex, version 2.15 [TeX Live 2017] (kpathsea + Thai support).
Scanning input file cp2223t.idx....done (85 entries accepted, 0 rejected).
Sorting entries....done (547 comparisons).
Generating output file cp2223t.ind....done (62 lines written, 0 warnings).
Output written in cp2223t.ind.
Transcript written in cp2223t.ilg.