For printed mortgage statements, the back page consists solely of a credit union "remit to" return address, formatted to fit into a window envelope.  There are no disclosures or other text on that page.  Similar to how credit card statements work, this address is on the back of the tear-off coupon that appears on the top of page 1 of the statement.  (This will be on the back of page 1 only, for a multi-page statement.) 

For CU*Spy eStatements, there is no PDF equivalent of this "back page."