Examine source code of Context (ctxt.io)

{
  "name": "Context (ctxt.io)",
  "short_name": "Context",
  "description": "Share whatever you see with others in seconds",
  "version": "1.0.6resigned1",
  "permissions": [
    "activeTab",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "96": "icon96.png",
    "128": "icon128.png"
  },
  "browser_action": {
    "default_title": "Context",
    "default_popup": "popup.html"
  },
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{ece728cd-9dea-4c45-8198-61199314d667}"
    }
  }
}