In addition to tye's early uses, Ovid makes a reference to "obfuperl" in this post dated 2000-12-22. Dropping the name of our favorite language gives you "obfu," although I suppose you could say that is an adjective describing a certain type of Perl.

Incidentally, you can use Super Search for this by putting obfu in the "Match text containing" box, and obfus in both the "Skip text containing" and "Skip titles containing" boxes, to weed out anything but the abbreviated form. This won't work to find a general string subscript (since you'd have to list a huge number of strings to exclude), but it works in this case since the sequence "obfu" is pretty rare outside of the word "obfuscate."