On the top right of the QMC window is the a context sensitive Help button that explains it.
I have pasted the Help text below.
To enable which QlikView clients, used to open and download the current document, which are presented through the QlikView AccessPoint, tick one of the following check boxes:
- IE Client, meaning the Microsoft Internet Explorer plugin client.
- Mobile Client, meaning the various mobile device applications.
- Full Browser and Small Device Version, meaning the AJAX client and AJAX for Small Devices.
- URL, to use other html pages, instead of the default, for displaying the AJAX pages, enter a valid path in this text box.