PDFLisp demo plugin
Acrobat Plug-in (sample) in Common Lisp
The binary bundle file is built by LispWorks 8.0 (64-bit) on macOS 10.15. It's confirmed working with Acrobat Pro 2017.
This sample plugin does nothing actually, I just do the handshake with Acrobat and stay inside it successfully. There's a log being printed at $HOME/Library/Application Support/Adobe/Acrobat/pdf-plugin-tools.log
.