Examine source code of Smashcast+

{
  "manifest_version": 2,
  "name": "SmashcastPlus",
  "short_name": "Smashcast+",
  "description": "Addons for Smashcast.tv",
  "version": "0.1.1resigned1",
  "author": "Ertzel",
  "icons": {
    "16": "images/smashcast+-icon-16x16.png",
    "48": "images/smashcast+-icon-48x48.png",
    "128": "images/smashcast+-icon-128x128.png"
  },
  "permissions": [
    "activeTab",
    "tabs",
    "storage",
    "*://www.smashcast.tv/*"
  ],
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "16": "images/smashcast+-icon-16x16.png",
      "48": "images/smashcast+-icon-48x48.png",
      "128": "images/smashcast+-icon-128x128.png"
    },
    "default_title": "Smashcast+",
    "default_popup": "popup/settings.html"
  },
  "background": {
    "scripts": [
      "themeManager.js"
    ]
  },
  "externally_connectable": {
    "matches": [
      "*://*.smashcast.tv/*"
    ]
  },
  "applications": {
    "gecko": {
      "id": "smashcastplus@ertzel.addons.mozilla.org",
      "strict_min_version": "42.0"
    }
  }
}