Examine source code of Cubari+ Context Menu

{
  "manifest_version": 2,
  "name": "Cubari+ Context Menu",
  "author": "isweethero",
  "version": "1.91",
  "browser_specific_settings": {
    "gecko": {
      "id": "isweethero2@gmail.com",
      "strict_min_version": "56.0a1"
    }
  },
  "description": "Context menu for cubari.moe and others art/anime related sites.",
  "permissions": [
    "contextMenus"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "icons/logo-48.png",
    "96": "icons/logo-96.png",
    "128": "icons/logo-128.png"
  },
  "browser_action": {
    "default_icon": "icons/logo-48.png"
  }
}