"Wombat" is the nickname for the front-end component in the Ambra stack.
A Wombat server hosts one or more sites. Each site represents an online publication. The same publication can be represented by more than one site, each with its own "theme" of front-end code -- for example, a desktop and mobile version of the site, or different localizations.
The "theme" is a means for the user to customize each site in various ways. It provides the user with options to override individual template and resource files, as well as containing several configuration options.
See the Ambra Project documentation for an overview of the stack and user instructions. If you have any questions or comments, please email firstname.lastname@example.org, open a GitHub issue, or submit a pull request.