[NTG-context] Windows 10, TeXLive 2016, and grep

Where can I find the applicable documentation for the grep script included in TeXLive on Windows? I.e. the one called with `mtxrun -script grep ...`. In particular I'm interested in knowing which grep options are available and which are not. `man mtx-grep` lists only 4 options (pattern, count, nocomment, and xml). Are those really the only options available? -- ✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝ Br. Samuel, OSB St. Anselm’s Abbey Washington, DC (R. Padraic Springuel) PAX ☧ ΧΡΙΣΤΟΣ