Currently, apk only allows package names where PACKAGE is accepted by the various tools (see Issue 7100 for request for full atoms).
In most cases, it would also make sense to operate on a .apk FILE in the same manner.
For instance,

apk info -L /tmp/linux-grsec-4.9.20-r0.apk
-or-
apk fix -i ./my-wip-package-0.11-r0.apk

(from redmine: issue id 7101, created on 2017-04-07)