Duelists of the Roses Documentation
This is where I plan to put technical information regarding the NTSC-U version of Yu-Gi-Oh! The Duelists of the Roses. This is in early days yet, so for now you will probably want to peruse this Google doc. I've accumulated enough information that working with the Google doc has become incredibly inconvenient, hence the move to here.
These docs are created by using Doxygen on header files. The generated docs are available at https://genericmadscientist.github.io/DotR-Documentation.
I assume familiarity with the C programming language. For modding the game it would also be useful to have the PS2 SDK docs and some knowledge of MIPS assembly.
This page is not here to provide a user-friendly guide on modding the game. For that purpose, the only publicly available tool I am aware of is yugioh-dor-deckedit by RenolY2. My understanding is it allows you to modify enemy decks and the starter decks, and you will have to grab PyQt yourself. I have no experience with it though.
If you have anything to add (additional information, links to more tools, etc.) feel free to send a pull request.