Examine source code of raesdecrypt

{
  "manifest_version": 2,
  "name": "raesdecrypt",
  "description": "raesdecrypt",
  "version": "1.0",
  "applications": {
    "gecko": {
      "strict_min_version": "48.0"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "raesdecrypt.js"
      ]
    }
  ],
  "permissions": [
    "activeTab",
    "tabs",
    "contextMenus",
    "storage",
    "<all_urls>"
  ],
  "icons": {
    "16": "icons/page-16.png",
    "32": "icons/page-32.png",
    "48": "icons/page-48.png"
  }
}