Examine source code of under the apple tree

{
  "manifest_version": 2,
  "version": "1.1",
  "name": "under the apple tree",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(105, 94, 88)",
      "toolbar_text": "rgb(252, 194, 158)",
      "frame": "rgb(38, 113, 97)",
      "tab_background_text": "rgb(241, 233, 223)",
      "toolbar_field": "rgba(252, 194, 158, 0.15)",
      "toolbar_field_text": "rgb(241, 233, 223)",
      "tab_line": "rgb(105, 94, 88)",
      "popup": "rgb(198, 148, 118)",
      "popup_text": "rgb(241, 233, 223)",
      "button_background_active": "rgb(105, 94, 88)",
      "button_background_hover": "rgb(198, 148, 118)",
      "frame_inactive": "rgb(38, 113, 97)",
      "icons_attention": "rgb(255, 255, 255)",
      "icons": "rgb(252, 194, 158)",
      "ntp_background": "rgb(75, 69, 66)",
      "ntp_text": "rgb(241, 233, 223)",
      "popup_border": "rgb(198, 148, 118)",
      "popup_highlight_text": "rgb(105, 94, 88)",
      "popup_highlight": "rgb(252, 194, 158)",
      "sidebar_border": "rgb(105, 94, 88)",
      "sidebar_highlight_text": "rgb(105, 94, 88)",
      "sidebar_highlight": "rgb(252, 194, 158)",
      "sidebar_text": "rgb(241, 233, 223)",
      "sidebar": "rgb(105, 94, 88)",
      "tab_loading": "rgb(252, 194, 158)",
      "tab_selected": "rgb(105, 94, 88)",
      "tab_text": "rgb(241, 233, 223)",
      "toolbar_bottom_separator": "rgb(105, 94, 88)",
      "toolbar_field_border_focus": "rgb(252, 194, 158)",
      "toolbar_field_border": "rgb(105, 94, 88)",
      "toolbar_field_focus": "rgb(252, 194, 158)",
      "toolbar_field_highlight_text": "rgb(241, 233, 223)",
      "toolbar_field_highlight": "rgb(38, 113, 97)",
      "toolbar_field_separator": "rgb(105, 94, 88)",
      "toolbar_field_text_focus": "rgb(105, 94, 88)",
      "toolbar_top_separator": "rgb(38, 113, 97)",
      "toolbar_vertical_separator": "rgb(198, 148, 118)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{69100637-d6a2-4dc6-8be2-82e58df454de}"
    }
  }
}