I get the sense that these disassembly/decompilation projects believe that some types of IP-laden asset data can be shipped embedded into the project — not necessarily "legally", but in that they'll likely get away with doing so indefinitely — as long as:
1. those assets are stored in proprietary formats that only the game code itself understands, and
2. no tool exists in the project to extract the assets from these proprietary formats into open formats, unless that tool itself exists only in source-code form in the codebase, and requires the ROM as an input to compile it (even if in the case of such a tool, the ROM is doing nothing but serving as a "key" to unlock compilation.)
Basically, if you have to prove you have a copy of the IP in order to make their embedded copy of the IP "legible", then it's very hard to construct an evidence-based DMCA takedown order that actually makes any coherent point about the project "distributing" said IP.
