Q: Would editing a game's .dll file, enabling something like dev tools and redistributing that file on github be illegal?

A: Yes. That is an infringing derivative work.

A: Editing and redistributing a game's .dll file without permission is likely to be illegal for several reasons:

1. Copyright infringement: Most games and their associated files are protected by copyright. Modifying and distributing copyrighted files without the owner's permission is generally considered copyright infringement.

2. End User License Agreement (EULA) violation: When installing or running a game, users typically agree to the game's EULA. These agreements often prohibit reverse engineering, modifying, or distributing the game's files. Editing and sharing a .dll file would likely violate the EULA.

3. Circumvention of security measures: If the game has anti-cheat or anti-tampering measures in place, modifying the .dll file to enable dev tools might be considered circumvention of security measures, which is illegal under the Digital Millennium Copyright Act (DMCA) in the United States and similar laws in other countries.

4. Potential for cheating: If the modified .dll file allows users to gain an unfair advantage in multiplayer games, it could be considered cheating, which may violate the game's terms of service and lead to account bans or legal action.

In summary, editing and redistributing a game's .dll file without the permission of the copyright holder is likely to be illegal due to copyright infringement, EULA violations, potential circumvention of security measures, and the possibility of enabling cheating.