Error on Debian 13:
Warning (bytecomp): 'loop' is an obsolete alias (as of 27.1); use 'cl-loop' instead.
Unfortunately emacs does not show a stack trace, see https://emacs.stackexchange.com/q/13532/12191.
Finding the culprit:
$ cd .config/emacs $ ag --el loop|grep -v cl-loop|grep loop elpa/yaxception-20150105.1452/yaxception.el:390: (loop for s in (apropos-internal "^[a-z\\-:/]+$") elpa/genrnc-20140612.1237/genrnc.el:302: (loop for f in (list genrnc--trang-jar-name genrnc--xsd2rng-jar-name genrnc--xsd2rng-xsl-name) elpa/yaxception-20150105.1540/yaxception.el:172: (loop for e in catch_or_finally
After that I simply removed genrnc and yaxception.