<p>The commit that introduced that odd escape+decode sequence is <a href="https://github.com/openstreetmap/openstreetmap-website/commit/248d0b863cde44881574ef01b974afeb2cad12e9" class="commit-link"><tt>248d0b8</tt></a> and as the commit comment explains I got it from <a href="http://monsur.hossa.in/2012/07/20/utf-8-in-javascript.html">http://monsur.hossa.in/2012/07/20/utf-8-in-javascript.html</a> as a magic hack to get JS to treat that header string as UTF-8 and decode it properly.</p>

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