Examine source code of Cool Slate (tab bar)

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Arcane",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-001-9c6d74e14860e77ee6f8f43e824bff25.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(34, 39, 53)",
      "toolbar_text": "rgb(233, 233, 233)",
      "frame": "rgb(34, 39, 53)",
      "tab_background_text": "rgb(195, 195, 195)",
      "toolbar_field": "rgb(51, 57, 78)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(51, 57, 78)",
      "popup": "rgb(51, 57, 78)",
      "popup_text": "rgb(210, 210, 210)",
      "button_background_active": "rgb(70, 80, 110)",
      "button_background_hover": "rgb(70, 80, 110)",
      "icons_attention": "rgb(255, 197, 69)",
      "icons": "rgb(146, 155, 172)",
      "ntp_background": "rgb(34, 39, 53)",
      "popup_border": "rgb(105, 119, 162)",
      "popup_highlight": "rgb(70, 80, 110)",
      "sidebar_border": "rgb(34, 39, 53)",
      "sidebar_highlight": "rgb(51, 57, 78)",
      "sidebar_text": "rgb(160, 172, 204)",
      "sidebar": "rgb(34, 39, 53)",
      "tab_loading": "rgb(70, 80, 110)",
      "tab_selected": "rgb(62, 70, 96)",
      "toolbar_bottom_separator": "rgb(34, 39, 53)",
      "toolbar_field_border_focus": "rgb(105, 119, 162)",
      "toolbar_field_focus": "rgb(51, 57, 78)",
      "toolbar_field_highlight_text": "rgb(191, 191, 191)",
      "toolbar_field_highlight": "rgb(70, 80, 110)",
      "toolbar_field_text_focus": "rgb(233, 233, 233)",
      "toolbar_top_separator": "rgb(34, 39, 53)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{845c136a-0857-4925-8260-893332ef0d67}"
    }
  }
}