Stickers on HP8568B and 8566B

[tkamiya]

I have both HP8568B and HP8566B.  On both of respective DISPLAY section, at bottom side of CRT bezel, there is this sticker, "Downloadable Program (DLP) installed.  To demo DLP, press blue SHIFT key and enter 10Hz". 

When followed, this does absolutely nothing other than displaying "Undef Key 10".


I think this was done at factory, not by user, since the stickers are exactly at the same location in exactly the same manner.

Does anyone know what this is about?

[ps]

When the unit was shipped, there was some software code (DLP) preloaded into memory. Tolerance curves for CATV, test procedures for GSM, statistic/math functions, whatever. Now it seems to be gone. Someone erased the RAM to factory defaults, the NVRAM battery was empty, or something on the controller PCB has been repaired.