Examine source code of Umbra Dark

{
  "manifest_version": 2,
  "version": "2.0",
  "name": "Umbra",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-009-f069b97f439938a011297c84464f0df6.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(0, 0, 0)",
      "toolbar_field": "rgba(251, 200, 89, 0.1)",
      "toolbar_field_text": "rgb(212, 175, 55)",
      "tab_line": "rgb(255, 255, 255)",
      "popup": "rgb(2, 2, 20)",
      "popup_text": "rgb(212, 175, 55)",
      "tab_loading": "rgb(255, 255, 255)",
      "bookmark_text": "rgb(251, 200, 89)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(180, 170, 139)"
    }
  }
}