Examine source code of Dark Optera

{
  "name": "Dark Optera",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "sdei-lg-tmb.png"
    },
    "colors": {
      "frame": "rgba(41, 42, 43, 1)",
      "tab_background_text": "rgba(171, 170, 168, 1)",
      "toolbar": "rgba(53, 58, 64, 1)",
      "bookmark_text": "rgba(88, 97, 105, 1)",
      "toolbar_field": "rgba(52, 56, 61, 1)",
      "toolbar_field_text": "rgba(69, 119, 168, 1)",
      "tab_line": "rgba(82, 82, 82, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{79bd2cb3-538b-4dbb-961c-18f9385ef9c5}"
    }
  }
}