They were created to help speed up and simplify the process
of editing and composing drum parts in REAPER.
There are four note maps for each library: default, renamed,
unique, and minimal. All of them use Toontrack's default MIDI
mapping scheme, which is partially based on the GM Drums standard.
The "unique" and "minimal" note maps also prioritize the GM Drums
standard over a more logical grouping of each kit piece.
For more details on the hows, whys, and whats, check out the
Ten years later! (2021): Still alive, but as you may have
noticed, still not updated with EZD2 or newer libraries.
Unfortunately, I don't have the time (or purchases) to update this,
but I'm glad to see it still being useful as a jumping off
point for other note map creators! Rock on!
Note maps and spreadsheet created by jeff alexander.
Pretty much everything else is very likely to be Toontrack, Platinum Samples, or Cockos's
copyrights and whatnot. Props to Notepad++.