<p>I can reproduce this on Opera 12.16, Build 1860 on Ubuntu 18.04 x64.</p>
<p>Here's the non obfuscated local version based on <a class="commit-link" data-hovercard-type="commit" data-hovercard-url="https://github.com/openstreetmap/openstreetmap-website/commit/3bc4f8e64f708b9e0bc8c7a4848cabff11d4d450/hovercard" href="https://github.com/openstreetmap/openstreetmap-website/commit/3bc4f8e64f708b9e0bc8c7a4848cabff11d4d450"><tt>3bc4f8e</tt></a></p>
<pre><code>[10.02.2020 23:03:31] JavaScript - http://localhost:3000/
Timeout thread: delay 4 ms
Uncaught exception: DOMException: NOT_SUPPORTED_ERR
Error thrown at line 3850, column 2 in <anonymous function: jQuery.readyException>() in http://localhost:3000/assets/application.debug-98541ea5446c89a752fb4e504c219d5b61bed92690ac65bf5bf0912a966f4423.js:
    throw error;
Error initially occurred at line 14709, column 4 in sanitizeHtml(unsafeHtml, whiteList, sanitizeFn) in http://localhost:3000/assets/application.debug-98541ea5446c89a752fb4e504c219d5b61bed92690ac65bf5bf0912a966f4423.js:
    var createdDocument = domParser.parseFromString(unsafeHtml, 'text/html');
called from line 15324, column 8 in _getConfig(config) in http://localhost:3000/assets/application.debug-98541ea5446c89a752fb4e504c219d5b61bed92690ac65bf5bf0912a966f4423.js:
    config.template = sanitizeHtml(config.template, config.whiteList, config.sanitizeFn);
called from line 14853, column 6 in Tooltip(element, config) in http://localhost:3000/assets/application.debug-98541ea5446c89a752fb4e504c219d5b61bed92690ac65bf5bf0912a966f4423.js:
    this.config = this._getConfig(config);
called from line 15389, column 10 in <anonymous function: Tooltip._jQueryInterface>() in http://localhost:3000/assets/application.debug-98541ea5446c89a752fb4e504c219d5b61bed92690ac65bf5bf0912a966f4423.js:
    data = new Tooltip(this, _config);
called via Function.prototype.call() from line 365, column 3 in <anonymous function: each>(obj, callback) in http://localhost:3000/assets/application.debug-98541ea5446c89a752fb4e504c219d5b61bed92690ac65bf5bf0912a966f4423.js:
    length = obj.length;
called from line 202, column 2 in <anonymous function: each>(callback) in http://localhost:3000/assets/application.debug-98541ea5446c89a752fb4e504c219d5b61bed92690ac65bf5bf0912a966f4423.js:
    return jQuery.each( this, callback );
called from line 15379, column 6 in _jQueryInterface(config) in http://localhost:3000/assets/application.debug-98541ea5446c89a752fb4e504c219d5b61bed92690ac65bf5bf0912a966f4423.js:
    return this.each(function () {
called from line 1472, column 8 in <anonymous function: control.onAdd>(layer, name, maxArea) in http://localhost:3000/assets/index.debug-a8e25a349a061b4c346f6a233b6490cb92f15d0614d0a20dfaae35d84ce94294.js:
    var item = $("<li>")
called from line 1523, column 6 in <anonymous function: control.onAdd>(map) in http://localhost:3000/assets/index.debug-a8e25a349a061b4c346f6a233b6490cb92f15d0614d0a20dfaae35d84ce94294.js:
    addOverlay(map.noteLayer, "notes", OSM.MAX_NOTE_REQUEST_AREA);
called from line 21726, column 2 in <anonymous function: addTo>(map) in http://localhost:3000/assets/application.debug-98541ea5446c89a752fb4e504c219d5b61bed92690ac65bf5bf0912a966f4423.js:
    var container = this._container = this.onAdd(map),
</code></pre>

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