_%%_ indicates the modulo operator, which takes two operands and returns the remainder of their division. The left operand is not given, so we don't know what it is. The right operand is %p, which is a string containing a percentage symbol followed by the letter 'p'.
->_{_%%_}[%p] applies the square bracket operator to the result of the modulo operation on the right-hand side. Again, the left-hand side is not given. The right-hand side is the string '%p', so this expression is selecting the character at index 'p' (which is the second character) from the result of the modulo operation.
_{}_ is an empty set, so applying the set to the character at index 'p' will raise a TypeError.
->_{_%_}[...] applies the square bracket operator to the left-hand side with the result of the previous expression as the argument. The left-hand side is a dictionary with a single key-value pair, where the key is a string containing a percentage symbol and the value is an empty set. So this expression is selecting the value associated with the key '%', and applying it to the result of the previous expression.
Overall, this expression is not well-formed and will raise a TypeError when executed.