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"
      ]
    }
  ]
}