/etc/skel/.profile is installed by the bash package.

    $ grep -C2 libpam-umask /etc/skel/.profile

    # the default umask is set in /etc/profile; for setting the umask
    # for ssh logins, install and configure the libpam-umask package.
    #umask 022

As far as I can tell, there is no libpam-umask package.
There is also now
https://salsa.debian.org/vorlon/pam/-/merge_requests/3/diffs?commit_id=56fb6980b1ff5936bb62e7c8313af8329e9f0d86
I suggest rewriting the comment as follow:

    # the default umask is set in /etc/profile; consider setting the umask
    # with pam-umask at /etc/pam.d/common-session{,-noninteractive}.
    #umask 022

Relatedly, the /etc/skel/.profile file indicates that “the default
umask is set in /etc/profile”. This is not true: /etc/profile contains
nothing about umask (at least, in a freshly installed Debian Bullseye).
In fact, even adding a umask command in /etc/profile seems to have no
effect in a Gnome session, maybe for reasons indicated at
https://unix.stackexchange.com/a/254923/.

I think it would be important to correct that comment: we ought to give
correct indications to at least those people who bother reading the
doc.