What the follwing phrase denotes "by or under the constotution"

"Jurisdiction and powers of all courts, except the Supreme Court, with respect to any of the matters in this list and, to such extent as is expressly authorized by or under the Constitution, the enlargement of the jurisdiction of the Supreme Court, and the conferring thereon of supplemental powers."



whether in the above quoted pasage the sentence "to such extent as is expressly authorized by or under the Constitution" is part of the sentence preceding it or is to be read with the sentecne following it.



2nd question is what is the meaning of "by or under the constitution" whether it denotes powers to be conferred by the constitution and exercise of the those powers under the constitution