We use "ODBC Driver" term in these papers, although it is all about developing KexiDB-level driver that is built on top of existing lower-level ODBC libraries. So by ODBC Driver we don't mean developing the layer between given database and ODBC protocols.
Old wiki page:  (TODO: migrate here)
There was old unused code in kexidb/drivers/odbs/ directory in Kexi 0.x, quickly disabled, and removed in Sep 2014 in Kexi 2.9.
Status: Experimental, not published, volunteers needed