This site introduces unknown Emanuel Bach (C. P. E. Bach).
ChatGPT4o writes as follows (please note that it may not be accurate):
Emanuel Bachʼs Fantasia in D Major Wq. 112-02 (H. 144) is a work characterized by its strong improvisational elements and unfolds in a free form. This fantasia is marked by unpredictable modulations and rhythmic changes, offering a musical adventure that surprises the listener. Bach skillfully expresses sudden emotional shifts, leaving a profound impression on the audience. The piece is rich in ornamentation and rapid passages, demanding a high level of technical skill from the performer. It is a work that showcases the richness of expression in his music and his innovative spirit that transcends the boundaries of the Classical era.