Access rights to system files

Working with IBM on a related issue, I determined that the *PUBLIC access for QADBXREF (and probably a bunch of other files) is set to an unusual configuration: the only access granted is Data Read authority. A standard *USE setting has both Data Read and Execute rights as well as Object Operational rights. Testing indicates that the latter (Operational) rights are required in order to execute SQL against the file.

My question is two-fold:

1. Is this the same setting others see on their systems? *PUBLIC having ONLY data read rights, with no object rights whatsover?

2. What does this setting mean? I can't even do a DSPPFM on the file. So why give the data read rights as all? This isn't the only file like this - other physical files in QSYS have similar settings. (Although interesingly enough logicals over those same physicals are accessible.)

And as a side comment, has it always been the case that you can't grant someone *USE access to a menu if someone else is using it? That seems a little bit finicky, especially for the MAIN menu.