What does the Federal Reserve intend to do with bonds it has purchased under QE? In New York Magazine's interview with investor Mike Burry (made famous by The Big Short), he claims Quantitative Easing has left the Federal Reserve with an extraordinarily high leverage ratio:


  What makes you most nervous about the future?
  
  Debt. The idea that growth will remedy our debts is so addictive for politicians, but the citizens end up paying the price. The public sector has really stepped up as a consumer of debt. The Federal Reserve’s balance sheet is leveraged 77:1. Like I said, the absurdity, it just befuddles me.


What are numerator and denominator in that leverage ratio? What are the Fed's options for what to do with all of the assets it has purchased? Is it even clear what it intends to do?
The leverage ratio, as always, is a ratio between liabilities and equity. It has really no significance, as the liabilities of the Fed, which are mostly dollars, need not to ever be paid back.

Only in the case of inflation would the Fed need to reduce its balance sheet (i.e., sell the public debt or MBS). Do note that the profit of the Fed goes back to the government, thus the debt that is sitting there is an asset and liability of the government at the same time, canceling out. That is, the net debt decreases as the Fed buys bonds from the market. You may also view it as inflation or a money tax that pays back the debt.