This is incomplete documentation regarding BYOND data.
There's a document which is supposed to contain protocol information but research hasn't gone far enough for it to be really worth anything.
byond-data-docs - documentation on BYOND formats
Written starting in 2020 by 20kdc (see README.md for additional credits)
To the extent possible under law, the author(s) have dedicated all copyright and related and neighboring rights to this software to the public domain worldwide. This software is distributed without any warranty.
You should have received a copy of the CC0 Public Domain Dedication along with this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
Note that said copy of the CC0 is in 'COPYING.txt'.
20kdc: This documentation, general structure research
extools (SpaceManiac, MCHSL, 1fbff5f83b23d39d38b1dfcb4cac8d9b et al.): DM bytecode information
Notes on this regard: This doesn't contain extools code. That said, if extools wants me to add their license here, ask via an issue or something.
Tomeno: important parts of string decryption and protocol decryption
BobOfDoom, NGGJamie, Crispy: Documented the BYOND Topic protocol at https://github.com/NGGJamie/byond-topics This was useful to understand BYOND packet framing, not covering encryption
Stephen001: Partial documentation of some format version (right now unknown but >= 307 < 494) at https://github.com/Stephen001/Lego
The Red Book (Super Saiyan X, LordAndrew, Kaiochao, DarkCampainger et al.): Informed me of the existence of modified types.
ZeWaka: Informed me of the existence of Lummox JR's information on the DMI format (at http://www.byond.com/forum/post/189170#comment1077677 )