You could have downloaded nightmod 0.2.3 for Mac from our software library for free. The actual developer of this software for Mac is Zachary Oakes. The most popular version of the tool is 0.2. Nightmod for Mac relates to Games.
From the developer:
Nightmod is a tool for making live-moddable games. You can view a game's code while it's running and inject changes by simply hitting the "Save" button. When you run Nightmod, you'll see several game templates: Platformer, Orthogonal, Isometric, Arcade, and Barebones. Each will start you off with a simple game that you can begin modifying.
You may want to check out more software for Mac, such as Reggie, Rawr or zeroWii, which might be related to nightmod.
