Examine source code of multi-grey theme

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "multi-grey theme",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-038-6c77b9d7dc86f50c6cd82f9c9b1f36f0.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(187, 192, 187, 0.88)",
      "toolbar_text": "rgb(0, 0, 0)",
      "frame": "rgb(219, 220, 219)",
      "tab_background_text": "rgb(0, 0, 0)",
      "toolbar_field": "rgba(255, 255, 255, 0.7)",
      "toolbar_field_text": "rgba(126, 181, 34, 0.96)",
      "tab_line": "rgba(64, 87, 254, 0.7)",
      "popup": "rgb(219, 220, 219)",
      "popup_text": "rgb(0, 0, 0)",
      "tab_loading": "rgba(64, 87, 254, 0.7)"
    }
  }
}