The U.S. Department of Justice is planning to publish once-confidential guidance memos that address disclosure of U.S. lobbying work for foreign companies and governments, shedding light on a federal law that has found new prominence as part of the special counsel’s case against former Trump campaign chairman Paul Manafort.

At least one law firm, Covington & Burling, said it had received a letter from the Justice Department announcing the plan to post online advisory opinions issued since January 2010. The advisory opinions reflect the Justice Department’s interpretation of the Foreign Agents Registration Act, or FARA, which in certain instances requires lobby shops and other firms to reveal their advocacy for a foreign entity.