There used to be a short hint the old netwatch docs, which is missing in the new manual:
When writing Up/Down/Test scripts for Netwatch, use the rtt-* elements instead of the thr-* elements. If the element names differ, their script-specific forms are listed in the description.
Nowhere to be found on Netwatch | RouterOS Manual
See also term "software documentation"/"proofreading" in the dictionary. Mikrotikish<->English conversion table/dictionary