Examine source code of GitHub Lines Viewed

{
  "manifest_version": 2,
  "name": "GitHub Lines Viewed",
  "version": "1.2.1",
  "description": "Replaces GitHub's 'files viewed' with 'lines viewed' instead.",
  "homepage_url": "https://github.com/ResponsiblyUnranked/github-lines-viewed",
  "icons": {
    "48": "icons/48.png",
    "96": "icons/96.png"
  },
  "permissions": [
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://github.com/*"
      ],
      "js": [
        "lines-viewed.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "popup/config.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_icon": "icons/48.png",
    "default_title": "GitHub Lines Viewed",
    "default_popup": "popup/config.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1f27e2d0-740c-46eb-978a-9c119bc60371}"
    }
  }
}