> Since those can reveal the source of the data, that reveals capabilities that the agency may not want to reveal, even if the data itself is no longer sensitive enough to classify.

Always 'member Trump and his release of a high resolution photograph from a satellite [1]. It took mere hours for people to work out which exact satellite was used to create the photograph and established a lower bound on its imaging capabilities.

[1] https://qz.com/1699833/what-we-can-learn-from-the-spy-satell...