I would also go for "... the expected structure of each LIST element ..."
and "... bindings of the corresponding parts of the element during ....".
And one or two other changes. That would give something like this:
(pcase-dolist (PATTERN LIST) BODY...)
Loop over a list, evaluating BODY for each element of LIST in turn.
PATTERN describes the expected structure of each LIST element and is
used to establish bindings to the corresponding parts of the element
during the evaluation of BODY. Undefined behavior results if the
structure of any LIST element is different from PATTERN.
For a description of PATTERNs, see `pcase'. See also `dolist'.
What do you think?