Acting AG Whitaker is dancing with the House Judiciary commitee.
He has been asked to testify voluntarily and has been given the questions in advance. They relate to his discussions with the President. He has been asked if he will invoke executive privilege.
He has said he will testify as long as it is guaranteed he will not be compelled via subpeona at a future date.
This seems to relate to a couple of things.
If he testifies voluntarily he can not answer questions if he chooses without invoking executive privilege.
If he is subpeonaed he is compelled to answer.
Also probably just playing for time, as he’ll seem less important to the Commitee once Barr is confirmed.