The Layout module both creates pages, and wraps existing pages in layout templates.
Backdrop's primary tool for positioning content is through layouts and blocks. A "layout template" is the template that defines the regions in which pieces of content may be placed. Each piece of content in this case is called a "block". Blocks may be placed multiple times in a single "Layout", and each block maintains separate settings. Each layout created saves to a configuration file, including all the settings for the blocks contained within it.
Layout module provides two distinct ways of rendering pages. It is capable of creating a stand-alone page that is created at any custom path specified by the user, and it can also "wrap" the content of any path provided by a module. In the case where a custom path is created, Layout module registers the path in the menu system through
hook_menu(). For wrapping module-provided pages, Layout module declares itself as the system-wide "route handler", as checked in menu_execute_active_handler(). Layout module then becomes responsible for calling the module-provided content as a block, and positions other blocks around the existing content.
This section provides guidance on developing layout templates for Backdrop.