I have the same thing here locally. ;o;
It's such an easy driver so I don't blame you for not saying you take dibs (also since I haven't said anything either).

I don't know where you're getting the 8000hz beeper from, copied from the other source code? Be mindful of the original copyright holder and GPL2 license.
It's a 1bit dac, directly controlled with d0.

Z80 is indeed 11.0592_MHz_XTAL / 4, and it matches the sound pitch here:


It is apparently from 1982.
I couldn't find other metadata, like which company manufactured it.

Here's my one: https://pastebin.com/153QVK6s
Looks like we both chose to use the tilemap system.