[temp.deduct.general]/p7 currently says

The substitution occurs in all types and expressions that are used in the function type and in template parameter declarations.

This should exclude exceptions specifications (since C++17) as we have a note saying:

The equivalent substitution in exception specifications is done only when the noexcept-specifier is instantiated, at which point a program is ill-formed if the substitution results in an invalid type or expression.

Should p7 also mention the "explicit-specifier" as p8 then does?

Only invalid types and expressions in the immediate context of the function type, its template parameter types, and its explicit-specifier can result in a deduction failure.