Good for them. Nonetheless, my point stands. In many places, it is illegal to reverse-engineer file formats, and in many places it isn't illegal but may as well be due to the potential costs of determining that it is legal.
(For instance, "The information in this document is furnished for informational use only, is subject to change without notice, and should not be construed as a commitment by Adobe Systems Incorporated. ". What happens if/when they pull said document?)
(Also: note that them documenting their file format is not the same thing as there being no potential liability for anyone to use said info.)