libgsasl7-dev - 1.8.0-8+deb10u1 main

GNU SASL is an implementation of the Simple Authentication and
Security Layer framework and a few common SASL mechanisms. SASL is
used by network servers (e.g., IMAP, SMTP) to request authentication
from clients, and in clients to authenticate against servers.
.
This package contain all files necessary for developing programs that
use GNU SASL. You will need this package if you want to build a
program that uses the GNU SASL library.