Is there Still a "Grand Mufti" of Jerusalem?

In the book “Oh Jerusalem”, reference is made to a muslim leader called a “Grand Mufti”. Is there one today? What are the duties of a Mufti?

Yes - https://en.wikipedia.org/wiki/Grand_Mufti_of_Jerusalem

A mufti is somebody who’s theologically qualified to issue fatwas, which are rulings on Islamic law.

Muhammad Ahmad Hussein from July 2006 to the present.