In 5.6, the module `malloc_test` was renamed to `misctest`, but the refernce in `pkg/kamailio/alpine/APKBUILD` was not changed to reflect this, so following the APK build instructions `/pkg/kamailio/README.md` fail.
I admittedly know very little about the APK package building process, but this looks very straight forward. I'll submit a PR once I've finished testing it out.
Closed #3091 via #3093.