Examine source code of GitHub Helpers

{
  "manifest_version" : 2 ,
  "name" : "GitHub Helpers",
  "version" : "1.0.0",
  "description" : "A set of helper functions for working with GitHub",
  "homepage_url" : "https://github.com/eshishkin/firefox-github-helpers-extension",
  "permissions" : [
    "activeTab" ,
    "storage" 
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "github-helpers-addon@eshishkin.org",
      "strict_min_version": "57.0"
    }
  },
  "browser_action" : {
    "default_icon" : "icons/extension_icon.png",
    "default_title" : "GitHub Helper",
    "default_popup" : "popup/settings_popup.html"
  },
  "content_scripts" : [
    {
      "matches" : [
        "https://github.com/*/pull/*/files*" 
      ],
      "js" : [
        "pr_helpers.js" 
      ]
    }
  ]
}