Examine source code of Utrecht University

{
  "name": "Utrecht University Botanic Gardens",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "Vườn bách thảo Utrecht51.png"
    },
    "colors": {
      "frame": "rgba(229, 230, 232, 1)",
      "tab_background_text": "rgba(230, 150, 150, 1)",
      "bookmark_text": "rgba(106, 112, 166, 1)",
      "tab_line": "rgba(124, 194, 145, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{cfc9cd6d-585b-4241-9e8a-0e5504c1a74c}"
    }
  }
}