Examine source code of SiteNote

{
  "manifest_version": 2,
  "name": "Siteflag",
  "version": "0.1.2",
  "permissions": [
    "tabs"
  ],
  "description": "Lets you take notes for websites.",
  "background": {
    "scripts": [
      "src/database.js",
      "src/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "assets/jquery-3.4.1.min.js",
        "src/siteflag.js"
      ]
    }
  ],
  "browser_action": {
    "browser_style": true,
    "default_popup": "popup/popup.html",
    "default_icon": {
      "16": "icons/icon_16.png",
      "32": "icons/icon_32.png"
    }
  }
}