efi

root@mordor:~#
root@mordor:~# mount /mnt/external; mount -o uid=1000 /dev/sda2 /mnt/external
mount: /mnt/external: can't find in /etc/fstab.
mount: /mnt/external: /dev/sda2 already mounted on /boot/efi.
root@mordor:~#
root@mordor:~# ll /boot/efi/
total 25
drwxr-xr-x 4 root root 4096 Dec 31  1969 ./
drwxr-xr-x 4 root root   19 Dec 13  2023 ../
drwxr-xr-x 4 root root 4096 Jul 28  2021 EFI/
-rwxr-xr-x 1 root root    8 Jun  1 16:28 foo.txt*
drwxr-xr-x 6 root root 4096 Dec 13  2023 grub/
root@mordor:~#