Invoking

  /usr/sbin/update-auctex-elisp --daemon

creates and leaves behind INITFILE in /, from

    if [ -n "${DAEMON_MODE}" -a "${DAEMON_MODE}" = 'true' ]; then
        export _UPDATE_AUCTEX_ELISP_DAEMON_MODE=${DAEMON_MODE}
        cd / && nohup ${0} ${_FLAVORS} </dev/null &>/dev/null &

and

        INITFILE=$(mktemp ./XXXXXXXX-el)

Perhaps best to always create INITFILE in /tmp?

This is with current Debian testing/unstable.

Best
-k

Indeed, I think mktemp -t should be used. Also, while testing this, I
found update-auctex-elisp outputs

/update-auctex-elisp: line 126: [: -gt: unary operator expected

due to unset EXIT_STATUS, which should have a default value of zero. Patch
for both issues:

--- update-auctex-elisp.eperl.orig 2024-04-09 08:19:06.232939684 +0200
+++ update-auctex-elisp.eperl 2024-04-09 08:19:23.472885040 +0200
@@ -107,11 +107,12 @@
  "(log to ${LOGFILE})..."
     if [ -z "${NO_ACT}" -o "${NO_ACT}" != 'true' ]; then
  exec {stdout}>&1 {stderr}>&2 &>${LOGFILE}
- INITFILE=$(mktemp ./XXXXXXXX-el)
+ INITFILE=$(mktemp -t XXXXXXXX-el)
  cat <<EOF >${INITFILE}
 (defun font-lock-fontify-syntactic-keywords-region (start end))
 EOF
     fi
+    EXIT_STATUS=0
     ${NO_ACT:+'echo'} ${FLAVOR} --batch --no-site-file --no-init-file \
  --load=${INITFILE} \
  --load=/usr/share/emacs/site-lisp/tex-site.el \