Originally, this was called the XBM10-2. It is probably one of the simplest transceivers you can make. It really works! These days there is less CW activity as people move to modes like FT8, but it is fun to make contacts with ultra simple homemade gear.
See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/10m-lesser-chirpy .