title: What does the pattern \d{10} mean?
body: <p>I'm validating a form via an XML schema, and I get this error: </p>
  
  <pre><code>[facet 'pattern'] The value '12' is not accepted by the pattern '\d{10}'
  </code></pre>
  
  <p>What does <code>\d{10}</code> mean? Where can I go to learn more about pattern facets?</p>