Taken from tjmarkham3:

I found some new hash codes after the 1.3.5 update for the Pre. Two of the new hash codes are:

* ##6346843277#
* ##2355273667#

Typing those codes into you're phone application toggles something called Experimental Mode. Does anybody know what Experimental Mode is?!?

The first code is labeled "CDTEST" in the source code while the second one is labeled "PPTEST."

The source code for hashes is located in this file if anyone is interested:
Anyone find out what experimental mode is or does? This is curious.