Examine source code of Tranquil

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#a9e8f2",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Tranquil",
  "manifest_version": 2,
  "description": "Stock credit: <a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/5e95c61dbb64c4aafb2401427c87ec2167d083bf3632f43163ff96bcfda742da/https%3A//www.freepik.com/vectorpocket\">vectorpocket</a>, <a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/2a802a6baf4f70afa7a6cf355e9c75796682fe6f3d13ab383bd21f8be679bad7/https%3A//www.freepik.com/kjpargeter\">Kirsty</a>"
}