While the law requires that identifying information of U.S. persons picked up during foreign surveillance be “masked,” high-ranking intelligence officials can request the identities be revealed if they feel the information is necessary to further understand the intercepts.
Former Obama national security adviser Susan Rice has openly acknowledged unmasking the identities of some senior Trump officials during the presidential transition but has strenuously denied ever leaking any identities and said nothing she did was politically motivated.
In 2017, Rep. Devin Nunes — a longtime critic of the Russia investigation — accused the Obama administration of improper unmasking of Trump transition officials after he secretly met with two national security officials at the White House who he said provided him with documents supporting his assertions.
Note how ABC tries to spin this story.