One of the libraries in node that I use obviously uses node-gyp and node-gyp apparently outputs a /build/config.gypi file (sometimes). I can't find any explanation of what this file is, beyond this issue on github.
Will anything be impacted if I delete this file? It's easy enough to find out the hard way. Thought it would be nice if this question was answered for the next person that finds this file and goes "huh?"
Judging by this, it looks like it's a set of configurations for Gyp, a tool used to build Node. When Node starts up, the .gypi is loaded like any other settings file.
To answer your question, it looks like deleting the file will lead to Node running with its defaults, ignoring any custom configs you set during installation.