symbol-package

(symbol-package symbol)

Lite: returns the same keyword shape find-package returns, so the two are eq-comparable: :keyword for a keyword, the qualifier of a package-qualified symbol, :cl for a standard symbol, :cl-user otherwise, and nil for an uninterned (#:) symbol. The compiled backends have no package registry at run time and cannot tell cl from cl-user: they answer :cl-user for both.