title: Log4jv2 Remove square brackets around NDC "%x"
body: <p>I would like to remove the square brackets around the Nested Diagnostic Context.
  This is the current pattern I have, is there a way to remove the square brackets from output?</p>
  <pre><code>#Console Appender
  appender.console.name=STDOUT
  appender.console.type=Console
  appender.console.layout.type=PatternLayout
  appender.console.layout.pattern=%d{yyyyMMdd HHmmss.SSS} %-5p [%-8.8t] %-15.15c{1} %3x %m%n
  </code></pre>
  <p>%3x outputs [content], I would like just content.</p>