Examine source code of Proton Deep Dark

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Proton Deep Dark",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(33, 33, 33)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(17, 17, 17)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(17, 17, 17)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(33, 33, 33)",
      "popup": "rgb(17, 17, 17)",
      "popup_text": "rgb(255, 255, 255)",
      "toolbar_bottom_separator": "rgba(255, 255, 255, 0)",
      "toolbar_field_border": "rgb(17, 17, 17)",
      "toolbar_top_separator": "rgba(41, 41, 41, 0)",
      "tab_loading": "rgb(33, 33, 33)"
    }
  }
}