Debian ignores PAM env variables (while Arch doesn't)

I have a weird issue with my Debian Sid system. I want to set a global environment variable in /etc/environment, which is supposed to be read by the pam_env module. Unfortunately, after having relogin in the system, the variable is not set. On another Arch Linux box, the same variable set in etc/environment is defined as expected. Just for testing, I tried to setup a local env variable in .pam_environment and, again, on Debian it's not being defined while on Arch it is. I'm using GDM on Debian and SDDM on Arch as login managers. What am I missing? Which (PAM or GDM) configuration files should I look at? EDIT: output of grep pam_env /etc/pam.d/* $ grep pam_env /etc/pam.d/* /etc/pam.d/atd:auth required pam_env.so /etc/pam.d/cron:# Read environment variables from pam_env's default files, /etc/environment /etc/pam.d/cron:# and /etc/security/pam_env.conf. /etc/pam.d/cron:session required pam_env.so /etc/pam.d/cron:session required pam_env.so envfile=/etc/default/locale /etc/pam.d/gdm-autologin:session required pam_env.so readenv=1 /etc/pam.d/gdm-autologin:session required pam_env.so readenv=1 envfile=/etc/default/locale /etc/pam.d/gdm-launch-environment:session required pam_env.so readenv=1 /etc/pam.d/gdm-launch-environment:session required pam_env.so readenv=1 envfile=/etc/default/locale /etc/pam.d/gdm-password:session required pam_env.so readenv=1 /etc/pam.d/gdm-password:session required pam_env.so readenv=1 envfile=/etc/default/locale /etc/pam.d/login:# file /etc/security/pam_env.conf. /etc/pam.d/login:session required pam_env.so readenv=1 /etc/pam.d/login:session required pam_env.so readenv=1 envfile=/etc/default/locale /etc/pam.d/polkit-1:session required pam_env.so readenv=1 user_readenv=0 /etc/pam.d/polkit-1:session required pam_env.so readenv=1 envfile=/etc/default/locale user_readenv=0 /etc/pam.d/su:# file /etc/security/pam_env.conf. /etc/pam.d/su:session required pam_env.so readenv=1 /etc/pam.d/su:session required pam_env.so readenv=1 envfile=/etc/default/locale