What IS this and who is Dave?

[hth]

Those are EPROMs, a 2732 for the lower 8-bits (L8) and a 2716 for the upper 2-bits packed into the bytes (U2). This is the original way to represent HP-41 ROM pages in EPROMs.

According to the label, it is the labels ROM for the David Assembler. It contains all the mainframe entry points to be used with the David Assembler. MNFR=mainframe I suppose.

David is David A. van Leeuwen, the author of it.

I suppose it is an EPROM box, which make I do not know, I have never seen any such device in real life, never could afford one back then.

I have no idea how to use either the ROM or the EPROM box, you probably need to have the David Assembler to make any use out of it, if it still works.

Håkan