This site introduces unknown Emanuel Bach (C. P. E. Bach).
ChatGPT4o writes as follows (please note that it may not be accurate):
C. P. E. Bachʼs Fantasia in F Major Wq. 112-15 (H. 148) is a work that stands out for its improvisational elements. This piece is characterized by its free form and bold modulations, presenting developments that surprise the listener. From the beginning to the end, it maintains an unpredictable flow, challenging the performerʼs expressiveness. Particularly, the alternation of rapid passages and slow sections skillfully intertwines tension and release. Emanuel Bachʼs richly emotional musicality is fully displayed, allowing one to feel his innovative compositional techniques. This fantasia leaves a profound impression on the audience.