The standard library Key api defines an argument type for (in particular) our red-black tree generics such as src/lib/src/red-black-map-g.pkg and src/lib/src/red-black-set-g.pkg.
The Key api source code is in src/lib/src/key.api.
The above information is manually maintained and may contain errors.
api {
Key;
compare : (Key , Key) -> Order;};