Examine source code of HypemDl

{
  "manifest_version": 2,
  "name": "HypemDl",
  "version": "1.1",
  "description": "direct download mp3 from hypem",
  "icons": {
    "48": "icons/border-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.hypem.com/*"
      ],
      "js": [
        "hypemdl.js"
      ]
    }
  ],
  "permissions": [
    "webRequest",
    "notifications",
    "downloads",
    "<all_urls>"
  ],
  "applications": {
    "gecko": {
      "id": "hypemdl@example.com"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}