Examine source code of SonicSeedBox

{
  "description": "SonicSeedBox Firefox Extension. One Click torrent download.",
  "manifest_version": 2,
  "name": "SonicSeedBox",
  "version": "5.1resigned1",
  "homepage_url": "https://www.sonicseedbox.com/",
  "icons": {
    "48": "icons/icon64.png"
  },
  "permissions": [
    "activeTab",
    "contextMenus",
    "notifications",
    "*://*.sonicseedbox.com/*",
    "https://mdn.mozillademos.org/files/2468/VeraSeBd.ttf"
  ],
  "background": {
    "scripts": [
      "set.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/icon64.png",
    "default_title": "SonicSeedBox",
    "default_popup": "popup/index.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.sonicseedbox.com/*",
        "*://*.mozillademos.org/*"
      ]
    }
  ],
  "applications": {
    "gecko": {
      "id": "admin@sonicseedbox.com"
    }
  }
}