Examine source code of Image saver

{
  "manifest_version": 2,
  "author": "Douile <25043847+Douile@users.noreply.github.com>",
  "homepage_url": "https://github.com/Douile/image-saver",
  "default_locale": "en",
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "version": "1.0.1",
  "icons": {
    "48": "/assets/logo_48.png",
    "96": "/assets/logo_96.png",
    "128": "/assets/logo_128.png",
    "254": "/assets/logo.svg"
  },
  "background": {
    "scripts": [
      "src/lib.js",
      "src/background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "/src/check.js"
      ],
      "run_at": "document_start"
    }
  ],
  "devtools_page": "devtools/devtools.html",
  "permissions": [
    "menus",
    "downloads",
    "devtools",
    "*://*/*"
  ]
}