Examine source code of HeyLink.me

{
  "description": "With just one click, add & save your current tab URL to HeyLink.me as a new link.",
  "manifest_version": 2,
  "name": "HeyLink.me",
  "version": "1.1",
  "icons": {
    "48": "icons/48.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "icons/32.png",
    "default_title": "Heylink.me",
    "default_popup": "popup/popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{bb34f4b1-30f5-4573-98db-3212b0eb884b}"
    }
  }
}