Notes about the WHMTHEME file extension:
Incorrect file associations could be the result of underlying issues within your PC system. As such it is highly recommended to scan your PC for invalid registry entries, unused processes and other unfavourable system settings to identify slowdown issues.
The WHMTHEME file type is primarily associated with 'WebHost Manager' by cPanel, Inc.. You have the capability to create and use your own themes on WebHost Manager. New themes need to be archived with tar, using the directory structure shown in WebHost Manager, and must have a file extension of .whmtheme.