Xmonad not recognized as window manager

[mathletedev]

I'm currently using xmonad; how can I display that in pfetch? In my config.fish, I have declared

set -gx PF_INFO "ascii title os uptime pkgs wm shell editor"

but all I'm seeing is

Previously, it was showing, but it is no longer displayed after an update to xmonad v0.17.0.