This site introduces unknown Emanuel Bach (C. P. E. Bach).
ChatGPT4o writes as follows (please note that it may not be accurate):
The Keyboard Concerto Wq. 26 and the Flute Concerto Wq. 166 are said to be arrangements of the Cello Concerto Wq. 170, which was originally composed for keyboard instruments. In this way, Emanuel Bach often adapted existing works to suit specific instruments. For more information about this piece, please refer to the description of the Keyboard Concerto Wq. 26.