Examine source code of Modern Red Pattern

{
  "manifest_version": 2,
  "version": "2.1",
  "name": "Modern Red Pattern",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/pattern.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(51, 51, 51)",
      "toolbar_field": "rgba(0, 0, 0, 0.22)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(204, 51, 51)",
      "popup": "rgb(51, 51, 51)",
      "popup_text": "rgb(238, 238, 238)",
      "tab_loading": "rgb(204, 51, 51)",
      "bookmark_text": "rgb(238, 238, 238)",
      "frame": "rgb(204, 51, 51)",
      "tab_background_text": "rgb(238, 238, 238)"
    }
  }
}