Here are the instructions
https://tn123.org/mod_xsendfile/
But I can't run apxs because that would involve using the plain-vanilla Apache2 that comes with Alma Linux (etc.) rather than the one managed by CWP.
How do I install this simple module in Apache2?
Quoteyum install httpd-devel -y
git clone https://github.com/nmaier/mod_xsendfile.git
cd mod_xsendfile
/usr/local/apache/bin/apxs -cia mod_xsendfile.c
systemctl restart httpd