I think these are files created by pack200.exe & unpack200.exe is run on them after installation to create the corresponding jar files.
So now I have a few questions
Why are only these 7 files run through pack200.exe. I assume its because they are bigger than other files. But it wouldn't take that much effort to pack all jar files & unpack them after installation.
The .pack extension suggests that these are packed but not gzipped. Again why would Oracle not do a gzip also? for eg with rt.jar packing reduces size from 45 MB to 12 MB, while adding gzip also reduces it to 6 MB.
Whatever the truth of all this may be, you won't find it here. This is a user to user forum, not Oracle support or a channel to the developers. All you will get here at best is valid post hoc reasoning: at worst, guesswork. And if you're trying to bring this issue to Oracle's attention, again this isn't the place to do it. Locking the thread.