What happens to the checked out objects during pkg build

I wasn't able to find a proper answer to this in oracle site or the pkg management guidebook. If say a BSFN is checked out, we know that in the \Work\NotChkdn.txt file it will say, object not checked in excluded from the build. Does this mean its excluded from both server and client build? so now when we deploy the new full pkg, the specs for that object will be missing in the enterprise server? or does it just take the last checked-in version of the object and builds that. Or somehow it leaves the last version of the object