diff --git a/lib/libpam/modules/pam_xdg/pam_xdg.8 b/lib/libpam/modules/pam_xdg/pam_xdg.8
--- a/lib/libpam/modules/pam_xdg/pam_xdg.8
+++ b/lib/libpam/modules/pam_xdg/pam_xdg.8
@@ -22,7 +22,7 @@
 .\" * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 .\" * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" * SUCH DAMAGE.
-.Dd August 22, 2024
+.Dd May 20, 2025
 .Dt PAM_XDG 8
 .Os
 .Sh NAME
@@ -42,10 +42,18 @@
 .Pa /var/run/xdg/<username> .
 .Pp
 The following option may be passed to the authentication module:
-.Bl -tag -width ".Cm runtime_dir_prefix"
+.Bl -tag -width indent
 .It Cm runtime_dir_prefix Ns = Ns Ar directory
 Use an alternate base directory
 .El
+.Sh ENVIRONMENT
+.Bl -tag -width indent
+.It Ev XDG_RUNTIME_DIR
+Specify the directory created by this module
+to enable use of a Wayland desktop.
+.El
+.Sh STANDARDS
+.Lk https://specifications.freedesktop.org/basedir-spec
 .Sh SEE ALSO
 .Xr pam 3 ,
 .Xr pam.conf 5