Look under the header "3C0-3CF EGA/VGA" at http://helppc.netcore2k.net/hardware/ports
That may contain some useful info, and at the risk of attention seeking self-advertising, possibly my Github page (see signature) will contain a few useful things. Probably nothing that will help with your immediate question but there is stuff about x86 assembly programming, memory dumping, screen dumping, and a Quick Basic program about video modes there.
I did a quick check of my games collection. It seems there several versions of EGA640.drv - I several of my games have a copy with a different size than the other.
Glancing with Microsoft Editor (it supports opening binary files) it seems each copy contains a header describing the driver followed by a repetitive data segment which is followed by a few kilobytes of varying binary values. Probably x86 machine code but don't hold me to it. The data segment looks like it could very well contain a color palette. Each version is approx 5-10kb in size.
Do not read if you don't like attention seeking self-advertisements!
Did you read it anyway? Well, you can find all sorts of stuff I made using various programming languages over here: