The file changebar.sty.patch is a patch that should be applied to changebar.sty version 1995/11/30 2.2h.

The file pdftexdir-patch is a patch to be applied to 3 files in the pdftexdir directory. This is for pdftex version 0.12n.

The file changebar.c is a new file that should be placed in the pdftexdir directory.