Why is mesa not installed on guacamole? Is it something configurable?

I am checking guacamole recipe and I find this (lines 146-149):

config file name must match daemon name

[ ! -f /etc/pam.d/xrdp-sesman ] && ${scripts_base}/config/mkxrdp-sesman > /etc/pam.d/xrdp-sesman

!!!! recipe option to overwrite xrdp sesman instead of showing a warning

grep "db=" /etc/pam.d/xrdp-sesman || echo "WARNING - no DB set in /etc/pam.d/xrdp-sesman. See mkxrdp-sesman"

Why is creating xrdp-sesman config on standard location (/etc/pam.d) instead of on portable service location (${etc_dir}/pam.d/)? The rest of xrdp config files are correctly located on portable location.
I thought all services (including xrdp) were ported to service location.

By the way, now that I understand the recipe I really like it, congratulations!