Examine source code of Simple Grey +B

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Simple Grey +B",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(200, 200, 200)",
      "toolbar_text": "rgb(50, 50, 50)",
      "frame": "rgb(200, 200, 200)",
      "tab_background_text": "rgb(150, 150, 150)",
      "toolbar_field": "rgb(50, 50, 50)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(52, 132, 252)",
      "popup": "rgb(50, 50, 50)",
      "popup_text": "rgb(200, 200, 200)",
      "icons_attention": "rgb(52, 132, 252)",
      "toolbar_field_border_focus": "rgb(52, 132, 252)",
      "toolbar_top_separator": "rgba(159, 117, 117, 0)",
      "tab_loading": "rgb(52, 132, 252)"
    }
  }
}