Examine source code of Dark with pattern shapes

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "BDark",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-030-0f935cfde055600d01a959c5c15353de.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(15, 15, 15)",
      "toolbar_text": "rgb(143, 143, 143)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(140, 140, 140)",
      "toolbar_field": "rgb(0, 0, 0)",
      "toolbar_field_text": "rgb(215, 215, 215)",
      "tab_line": "rgb(255, 255, 255)",
      "popup": "rgb(14, 14, 14)",
      "popup_text": "rgb(226, 226, 226)",
      "tab_loading": "rgb(255, 255, 255)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f5edcf3a-d13e-4040-b395-63b4690c19cf}"
    }
  }
}