This site introduces unknown Emanuel Bach (C. P. E. Bach).
ChatGPT4o writes as follows (please note that it may not be accurate):
Emanuel Bachʼs Solfeggio in C minor (Wq. 117-2) is a short yet dramatic and impressive piece. The key of C minor imparts tension and depth to the composition, characterized by its unique harmonic progressions and rhythmic variations. The improvisational nature stands out, encapsulating the charm of the empfindsamer Stil. The piece demands dynamic expression throughout, requiring performers to possess advanced technique and sensitivity. While it was also appreciated as a study piece for learners of the time, its high level of musical completeness is particularly noteworthy.