A new construction relating enriched categories and internal ones in an extensive ambient

A new construction to associate an internal category to an enriched one is presented. The key concept is that of extensive ambient category, and the construction follows the one that associates a category whose idempotents split to a given one. The association turns out to be functorial and left adjoint to an already known one when we restrict to a particular class of internal categories whose idempotents split in some canonical way and impose a size restriction.