The SSTF contains $2.6 trillion in interest bearing, non-market T-bills. The SSTF is part of our $23 trillion and growing national debt. Those T-bills are backed by the full faith and credit of the USG just like any other T-bill.
Borrowing from our own “investment” T-Bonds... which are of course NOT owned mostly by US citizens... more like institutional buyers (insurance) and.... the chi-coms. Just perfect!