Layout::delete in core/modules/layout/includes/layout.class.inc

Delete this layout.

Layout::disable in core/modules/layout/includes/layout.class.inc

Disable a layout.

Layout::enable in core/modules/layout/includes/layout.class.inc

Enable a layout.

Layout::revert in core/modules/layout/includes/layout.class.inc

Revert a layout to a module-provided default.