How to change password or add new username/password in xmapp

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I newly installed XAMPP on MAC. The XAMPP web access requires authentication. I found the .htaccess in the folder, in which the config shows AuthUserFile /Application/XAMPP/xamppfiles/lib/xampp.users The content of xampp.users is something like "xampp:eU2oSlesk0c9h". I tried the pair as username and password to login the web authentication but failed.

My question is how to configure xampp.users, to add/to modify, so that I have a valid account to access XAMPP http web. Thanks. I failed to find any reference about xampp.users on internet.
http://superuser.com/questions/716920/how-to-change-password-or-add-new-username-password-in-xmapp-users