The function package-flagged-p
is the predicate for whether the package package is flagged with the keyword flag.
Current valid values for flag are:
Packages that are part of the LispWorks implementation. You must not add definitions to them.
Packages that are fully documented (that is, all external symbols are documented), and all external symbols are intended for your use.
LispWorks User Guide and Reference Manual - 13 Feb 2015