The standard library quickstring_binary_set package implements quickstring__premicrothread-keyed sets. (Possibly a misnomer, since operations like intersection and union are not supported.)
The quickstring_binary_set package implements the Set API via binary_sap_g from src/lib/src/binary-set-g.pkg.
The quickstring_binary_set package source code is in src/lib/src/quickstring-binary-set.pkg.
See also: quickstring_binary_map.
See also: quickstring_red_black_set. The above information is manually maintained and may contain errors.