The “deeply equals” is being produced by the “to.be.eql” assertion which is part of the Chai assertion library.
Expect / Should - Chai (chaijs.com)
The best way to check for statuses is to use “pm.response.to.have.status” which is a special assertion linked to the pm.response function.
pm.test("Status code is 200", () => {
pm.response.to.have.status(200);
});