What is the “main file” property when doing bower init?

According to the Bower.io documentation

main

Recommended Type: String or Array of String

The primary acting files necessary to use your package. While Bower
does not directly use these files, they are listed with the
commands bower list –json andbower list –paths, so they can be used
by build tools.

Preprocessor files like CoffeeScript should be compiled.Do not include
minified files.Filenames should not be versioned (Bad:
package.1.1.0.js; Good: package.js).

I think it’s more for the package management, and build tools like Grunt and Brunch. For example, Bootstrap’s bower.json looks like :

{
  "name": "bootstrap",
  "version": "3.0.3",
  "main": [
    "./dist/css/bootstrap.css",
    "./dist/js/bootstrap.js",
    "./dist/fonts/glyphicons-halflings-regular.eot",
    "./dist/fonts/glyphicons-halflings-regular.svg",
    "./dist/fonts/glyphicons-halflings-regular.ttf",
    "./dist/fonts/glyphicons-halflings-regular.woff"
  ],
  "ignore": [
    "**/.*",
    "_config.yml",
    "CNAME",
    "composer.json",
    "CONTRIBUTING.md",
    "docs",
    "js/tests"
  ],
  "dependencies": {
    "jquery": ">= 1.9.0"
  }
}

When I build in Brunch, it pulls these files from my bower_components folder in my public folder.