Examine source code of Roamit

{
  "manifest_version": 2,
  "name": "Roamit",
  "description": "Integrate Firefox with Windows Timeline, and send links to your Android or Windows phone quickly.",
  "version": "0.2.3resigned1",
  "browser_action": {
    "default_icon": "icon19.png",
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "background": {
    "scripts": [
      "jquery-3.3.1.min.js",
      "initScript.js",
      "consts.js",
      "common.js",
      "remoteSessions.js",
      "background.js",
      "background-timeline.js"
    ]
  },
  "permissions": [
    "contextMenus",
    "tabs",
    "https://roamit.ghiasi.net/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{59e40400-9ce9-48c0-87fb-e1b107e92185}"
    }
  }
}