The Fragmention processing model says “the outer element that contains the text completely” which is not precisely defined. Depending on how leading/trailing text is handled, especially space collapsing (Issue #7), it may affect which element can be considered to “contain” the text “completely”.
In addition “the outer element” could always be returned as the body element, which is clearly not the intent of the Fragmention specification. The processing model needs some clarifications about the most precise, or minimal, or most deeply nested element or whatever is the intended meaning of the specification for “the outer element”.