Examine source code of Followed By

{
  "manifest_version": 2,
  "name": "Followed By",
  "description": "Followed By uses GitHub’s public API to fetch mutual followers for every profile you visit, straight to the profile page!",
  "version": "1.0.1",
  "icons": {
    "16": "assets/16.png",
    "32": "assets/32.png",
    "48": "assets/48.png",
    "128": "assets/128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://github.com/*",
        "https://github.com/*?tab=*"
      ],
      "exclude_matches": [
        "https://github.com/*/*",
        "https://github.com/"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "permissions": [
    "storage",
    "https://api.github.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "web_accessible_resources": [
    "src/app.js",
    "src/utils/api.js",
    "src/utils/storage.js",
    "src/utils/aggregators.js",
    "src/utils/views.js"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{1c8d94f5-d821-4af1-8973-00cc52989a95}"
    }
  }
}