Rare Philips PM9267 data hold probe

[Nexrem]

Hey, new around here.
Recently I obtained a Rare Philips PM9267 data hold probe. There is practically no information on it anywhere on the internet. There is one seller selling it for 169 EUR (which is quite exorbitant). I got mine for < 15 EUR from some nice elderly person here in Bulgaria who was happy it was going to a new home.

I have a Philips PM2534 DMM that's compatible with it. It works well. Since there is practically no info about these I thought I'd post pictures and maybe ask some questions as I'm not sure what one of the indicators does.

When connected to the DMM you can make any measurement using the Volt/Ohm input. This means you can measure resistance, AC and DC volts and caps. Pressing the button toggles the LED on the probe and "holds" whatever value on the display on the DMM.

There is a ground passthrough on the plug to the DMM as well as a single pin sticking out on the front of the probe marked "0". This is connected directly to ground and is used to connect for example a local crocodile clip or another probe for ease of use.

The probe has really nice build quality and is great to use. However I still havent figured out what the = speaker icon is for. I thought it was some continuity tester but it doesn't do anything. I thought maybe it lights up when the value being hold "equals" another measured value for quickly probing relative grounds for example, but it doesnt seem to be that either. Maybe my DMM doesn't have this feature?

[AVGresponding]

I'd have guessed it's a visual continuity indicator. I'd further guess that if it doesn't light when it should, that it has been popped by someone applying too many angry pixies...