What are the “~orig” files in OS X?

In the /etc folder of my system (OS X 10.8.2) I see a bunch of files named with the "~orig" suffix (e.g hosts~orig, passwd~orig, etc). What are these?


Those are the leftovers of OS upgrade.

The OS X upgrade saves previous configurations that's going to be changed.

The date of ~orig file should correspond with the OS upgrade.