"Main" value in package.json file in Protractor project

I launched the npm init command in my Protractor project in order to generate a package.json file.

The default value for the "main" field is "index.js", which makes no sense in my project. Anyway, I left it like that and my npm install ran well.

Is the "main" field parameter important in a Protractor project? If so, which file value I put in it, and how will it be used? Thank you.

via Y-B Cause