Examine source code of Pixlr Plus

{
  "manifest_version": 2,
  "name": "Pixlr Plus",
  "version": "1.4",
  "description": "Enhance your Pixlr experience!",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://pixlr.com/*"
      ],
      "js": [
        "contentScript.js"
      ]
    }
  ],
  "permissions": [
    "storage",
    "https://pixlr.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{8c96f70e-6217-4d10-a0a2-6c32c8222d99}",
      "strict_min_version": "42.0"
    }
  },
  "icons": {
    "48": "logo.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "logo.png"
    }
  }
}