Examine source code of clip.so

{
  "manifest_version": 2,
  "name": "clip.so",
  "description": "Cross browser bookmarks",
  "version": "1.0.10",
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "js": [
        "js/content.js"
      ],
      "matches": [
        "https://clip.so/*",
        "http://localhost/*"
      ]
    }
  ],
  "background": {
    "scripts": [
      "js/background.js"
    ]
  },
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "permissions": [
    "bookmarks",
    "storage",
    "*://*/*"
  ]
}