Game Maker 8 data.win unpacker and disassembler (non-YYC, specifically made for Undertale), based on libaltar and Mirrawrs' data site.

Contains a lot of pointer-littered spaghetti code, because it's basically a continuation of libaltar, but in C#.

I'm not sure if this counts as 'redistribution of modified [libaltar] source', but including their notice just in case.