: For Marathon 2 and Infinity, editing the files certainly does seem simple enough, but for Marathon 1, neither JUICE nor Weland seem to be able to open the data files.
Our eventual goal is to allow M2 levels to ask for M1-style behavior. Aleph One essentially translates M1 physics, maps, etc. into M2 format, and uses new mission and environment flags to enable M1 features that M2 dropped or changed. Once we finish cleaning up that process, Weland will read and write those new flags, and Aleph One will be able to run an M2 level under M1 rules. Then we can produce an editable version of the Marathon 1 maps, so you can mod them in Weland.
The licensing is still murky. The trilogyrelease site doesn't really grant anything except the right to download and play; we didn't even bundle the files with Aleph One until we got Bungie's permission ourselves. It's not clear what is covered by the CC license from the Infinity source code release. The scenario files were not part of that download, so it might apply only to the "content" parts of the source code download (some story notes, films, etc.).
In my personal opinion, Bungie is leaving it vague so they have legal recourse to stop someone from exploiting Marathon, but they wouldn't mind free community efforts like a co-op mod. That's just speculation and I have not discussed these issues with any Bungie employee.
