“The Troublemaker” is a brisk account of the life and work of Jimmy Lai, the media mogul and democracy activist currently on trial for national security offenses.

He had been hailed by Chinese state media as a model for his efforts to promote Beijing’s interests in the United States. He was in fact an F.B.I. informant.

The Americans released, among others, a Chinese intelligence officer who was serving a 20-year sentence in the United States.

Jimmy Lai, who is charged with national security offenses, testified that his newspaper “carried a torch to the reality” of people’s desire for freedom in the city.

The 45 defendants, including Joshua Wong, were at the forefront of the opposition movement crushed by Beijing. Many had already been in jail for years.