Examine source code of Preening Mermaid

{
  "manifest_version": 2,
  "version": "2.0",
  "name": "Preening Mermaid",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(131, 199, 186, 0.1)",
      "toolbar_field": "rgba(255, 255, 255, 0)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgb(255, 181, 0)",
      "popup": "rgb(214, 255, 247)",
      "popup_text": "rgb(0, 80, 64)",
      "tab_loading": "rgb(255, 181, 0)",
      "bookmark_text": "rgb(0, 119, 96)",
      "frame": "rgb(214, 255, 247)",
      "tab_background_text": "rgb(29, 61, 61)"
    }
  }
}