While in trixie, I was modifying /etc/pam.d/su file (to add TOTP configuration)
and I was relying on the fact that /etc/pam.d/su-l was including the former
one. However, in Debian testing /etc/pam.d/su-l does not include it, which
broke my configuration.

I think it would be good if this change is documented in the list of changes in
NEWS.Debian so that it is displayed at installation time (if apt-listchanges is
installed, of course).