asdf:component-version

(asdf:component-version component)

Reader: the :version string the system's defsystem declared, or nil when it declared none. Only a plain string literal is recorded — a .asd is parsed as data, so ASDF's (:read-file-form "version.sexp") indirection (and any other computed spelling) is never evaluated and answers nil. A component file has no version of its own.

Backend support

Works on all four backends, on any component object (asdf:find-system's systems and their asdf:component-children).