Examine source code of Arc Theme

{
  "manifest_version": 2,
  "applications": {
    "gecko": {
      "id": "arc-theme@afnankhan",
      "strict_min_version": "67.0"
    }
  },
  "name": "Arc Theme",
  "version": "2020.8.28",
  "description": "Arc theme for Firefox",
  "theme": {
    "colors": {
      "frame": "#E7E8EB",
      "frame_inactive": "#E7E8EB",
      "tab_text": "#5C616C",
      "tab_background_text": "rgba(82, 93, 118, 0.8)",
      "tab_line": "#5294E2",
      "tab_loading": "#5294E2",
      "icons_attention": "#5294E2",
      "toolbar": "#F5F6F7",
      "toolbar_top_separator": "#CFD6E6",
      "toolbar_bottom_separator": "#DCDFE3",
      "toolbar_vertical_separator": "#DCDFE3",
      "toolbar_field": "#FFFFFF",
      "toolbar_field_text": "#5C616C",
      "toolbar_field_border": "#CFD6E6",
      "toolbar_field_separator": "#CFD6E6",
      "toolbar_field_focus": "#FFFFFF",
      "toolbar_field_border_focus": "#CFD6E6",
      "toolbar_field_highlight": "#5294E2",
      "toolbar_field_highlight_text": "rgba(255, 255, 255, 0.9)",
      "button_background_hover": "rgba(0, 0, 0, 0.085)",
      "button_background_active": "#5FA1E6",
      "bookmark_text": "#5C616C",
      "popup": "#FFFFFF",
      "popup_text": "#5C616C",
      "popup_border": "#DCDFE3",
      "popup_highlight": "#5294E2",
      "popup_highlight_text": "rgba(255, 255, 255, 0.9)",
      "sidebar": "#F5F6F7",
      "sidebar_text": "#5C616C",
      "sidebar_border": "#DCDFE3",
      "sidebar_highlight": "#5294E2",
      "sidebar_highlight_text": "rgba(255, 255, 255, 0.9)",
      "ntp_text": "#5C616C",
      "ntp_background": "#FFFFFF"
    }
  }
}