server/templates/beforeContent.html

<div style="background-color: #F9F9F9; margin-top: 1em; padding: 10px;  border: 1px solid #DDD; font-size: 14px;">
  This is a <strong>beforeContent.html</strong> file content included by the
  <a href="https://confluence.jetbrains.com/display/TW/StaticUIExtensions">StaticUIExtensions plugin</a>.
  This page will only be shown on overview pages.
  Refer to 
  <pre>[TeamCity Data Directory]/config/_static_ui_extensions/static-ui-extensions.xml</pre> 
  for more details.
</div>