Sometimes the technicians don't know, they are undocumented features left as Easter eggs or back doors by the firmware programmers for internal development use.
Right, it was meant for the developers of the camera for only testing the limits of the sensor, and then they would program those limits into the camera. Once the testing was done, the next release of firmware would eradicate that feature.
In the case of the E-500 (and E-400, as well as early firmware E-300's), that feature was forgotten until the details were posted on the BIOFOS site. After that the next release of firmware got rid of that "feature" (or changed the sequence).
Anyway, there hasn't been a camera released since that had that feature available to the end user (at least that has been found); that means on the E-330, E-510/20, E-410/20, E-3, E-5, not to mention all the Micro "E's".
