title: Best way to detect mobile users in Magento
body: <p>What is the best way to detect if user is a mobile user in code level?</p>
  
  <p>Admin can set regex based rules to detect and switch themes based on user agent but seems like this functionality is "protected" inside api and is not available as a set of methods every developer can use. </p>
  
  <p>I understand that devs and designers should arrange their functionality in theme folders to be available/unavailable but this is rather hard requirement for extension providers as the regex rules can be somewhat loosely defined and admin does not have to specify if a theme is intended for mobile users</p>
  
  <p>So maybe someone has a good method to sniff this out from core already (without implementing stuff over again to be public instead protected that is already available <code>core/design_package</code>)?</p>