The ENTITIES type does not allow mixed content.
There is no restriction on type derivation.
Allows any attributes from other namespaces (lax validation).
ENTITIES is a list of ENTITY. There are several restrictions on the list. The number of items in the list is greater than or equals to 1. There are several restrictions on the list item value. The schema processor collapses value's whitespace. The value must match "[\i-[:]][\c-[:]]*".