Examine source code of Velocity Text Expander

{
  "manifest_version": 2,
  "name": "Velocity Text Expander",
  "description": "manifest.json description",
  "version": "1.8.5",
  "short_name": "Velocity",
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAnZq3hN1td1lfiD3QnCd+QpZMcVf3UOoW0mFudfhdJI2JFkeUKcXelhXEXHmb9m3nyQ9kLrMR5kBKRqREy+uGulvl1C+Vj20lxHF/hm7ZWc0fWmLyhZ001o0+pP/x7/90YyjISlwLcaAza8ltKkjIuoTu4VCLGe7549DUzEIMEGreOSMsX5XKCt3WVOAS1jCvV0BHTqUJBykOW8NapPpxhkLKzoEHTLEE0sJxcyTSRCl3aXO+JC/pD8NTqRg+g4SVhnZaQCa3NzXWOwpWX2SzQUuGrz9J1c010iwRyj/p765zpj/xcGG0PWdvGbs0bsSl25igW7x1j9TM3TtXBlU4AwIDAQAB",
  "permissions": [
    "storage",
    "activeTab",
    "identity"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "velocity@text-expander",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Default Popup Title",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "all_frames": true,
      "match_about_blank": false,
      "js": [
        "content-scripts/content.js"
      ]
    }
  ]
}