Examine source code of why this

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "why",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-005-f5f3cf677b1f132c75ddc7bd319dd1fc.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(81, 105, 117)",
      "toolbar_text": "rgb(109, 42, 55)",
      "frame": "rgb(52, 0, 255)",
      "tab_background_text": "rgb(0, 255, 93)",
      "toolbar_field": "rgb(232, 232, 249)",
      "toolbar_field_text": "rgb(205, 206, 219)",
      "tab_line": "rgb(83, 41, 50)",
      "popup": "rgb(234, 241, 231)",
      "popup_text": "rgb(193, 207, 190)",
      "button_background_active": "rgb(53, 29, 172)",
      "button_background_hover": "rgb(246, 0, 255)",
      "icons_attention": "rgb(246, 0, 255)",
      "tab_text": "rgb(85, 66, 189)",
      "tab_loading": "rgb(83, 41, 50)"
    }
  }
}