Examine source code of idontknow

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "last",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-026-829b05416f823e170310e7c826ad1bec.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(42, 45, 42)",
      "toolbar_text": "rgb(142, 174, 96)",
      "frame": "rgb(42, 45, 42)",
      "tab_background_text": "rgb(143, 213, 124)",
      "toolbar_field": "rgba(36, 38, 36, 0.7)",
      "toolbar_field_text": "rgb(199, 234, 139)",
      "tab_line": "rgb(143, 213, 124)",
      "popup": "rgb(42, 45, 42)",
      "popup_text": "rgb(132, 168, 67)",
      "popup_highlight_text": "rgb(132, 168, 67)",
      "popup_highlight": "rgb(58, 62, 58)",
      "toolbar_field_focus": "rgb(36, 38, 36)",
      "toolbar_field_text_focus": "rgb(142, 174, 96)",
      "tab_loading": "rgb(143, 213, 124)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f6fbae2e-079d-4a04-a3cc-1b7f131d434e}"
    }
  }
}