Most of the cPanel-specific configuration options for ClamAV are saved in this file:
/usr/local/cpanel/3rdparty/etc/cpclamav.conf
For example to see what users are configured to use ClamAV you can run this command:
grep CLAMAVOVERRIDEUSERS /usr/local/cpanel/3rdparty/etc/cpclamav.conf
CLAMAVOVERRIDEUSERS=domain1223,cptest1,cptest2