hw-json-standard-cursor is support library for hw-json, a succinct JSON parsing library.
It is used to create "interest-bits" (*.ib.idx) files and "balanced-parenthesis" (*.bp.idx) files. These can then be loaded by the hw-json library to enable parsing of parts of the original JSON file without deserialising the entire JSON file into objects in memory.
For more information see hw-json.