Examine source code of Nightlight

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Nightlight",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-026-829b05416f823e170310e7c826ad1bec.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(65, 95, 145)",
      "toolbar_text": "rgb(132, 200, 238)",
      "frame": "rgb(43, 41, 71)",
      "tab_background_text": "rgb(176, 146, 79)",
      "toolbar_field": "rgb(45, 45, 90)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(62, 245, 255)",
      "popup": "rgb(65, 95, 145)",
      "popup_text": "rgb(132, 200, 238)",
      "button_background_active": "rgb(92, 82, 229)",
      "button_background_hover": "rgb(132, 127, 200)",
      "frame_inactive": "rgb(1, 0, 3)",
      "icons_attention": "rgb(132, 127, 200)",
      "icons": "rgb(236, 220, 152)",
      "ntp_background": "rgb(33, 44, 71)",
      "ntp_text": "rgb(255, 201, 6)",
      "popup_border": "rgb(132, 200, 238)",
      "popup_highlight_text": "rgb(255, 228, 132)",
      "popup_highlight": "rgb(76, 111, 168)",
      "sidebar_border": "rgb(29, 29, 75)",
      "sidebar_highlight_text": "rgb(255, 228, 132)",
      "sidebar_highlight": "rgb(76, 111, 168)",
      "sidebar_text": "rgb(159, 216, 255)",
      "sidebar": "rgb(65, 95, 145)",
      "tab_background_separator": "rgb(132, 200, 238)",
      "tab_loading": "rgb(62, 245, 255)",
      "tab_selected": "rgb(43, 41, 71)",
      "tab_text": "rgb(132, 200, 238)",
      "toolbar_bottom_separator": "rgb(62, 245, 255)",
      "toolbar_field_border_focus": "rgb(255, 228, 132)",
      "toolbar_field_border": "rgb(29, 29, 75)",
      "toolbar_field_focus": "rgb(45, 45, 90)",
      "toolbar_field_highlight_text": "rgb(255, 228, 132)",
      "toolbar_field_highlight": "rgb(29, 29, 75)",
      "toolbar_field_separator": "rgb(29, 29, 75)",
      "toolbar_field_text_focus": "rgb(62, 245, 255)",
      "toolbar_top_separator": "rgb(29, 29, 75)",
      "toolbar_vertical_separator": "rgb(62, 245, 255)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{394c76ef-bfa9-4e28-9e82-2d9459063089}"
    }
  }
}