There is only one file type that uses the .WEBTEMPLATE extension:
Template created by iWeb, a user-friendly Web design program; contains pre-designed templates organized under themes such as Leaf Print, Fine Line, Goldenrod, and Modern Frame; opened through the application.
NOTE: iWeb was part of Apple's iLife application suite.
Black Blank.webtemplate - Blank template file under the Black theme.
|Apple iWeb — Discontinued||Paid|
Updated: May 3, 2013