Where is /cow for Linux booted from LiveUSB?

I wanted to see what files are added on top of ISO 9660 when LiveUSB Linux is running. When booted with persistence upper and work folders are on USB drive clearly seen. I run mount on Linux booted from LiveUSB "usual way" (w/out persistence) and saw / is mounted via overlayfs and upperdir=/cow/upper. But sudo ls /cow gives no such file or directory. Where is /cow and how to see its contents? Added 1: I was able to extract contents of initrd from liveUSB via unmkinitramfs (see https://unix.stackexchange.com/a/495524/446998) $ find . -type f -exec bash -c 'cat {} | grep "/cow/upper" && ls -l {}' \; if [ ! -d /cow/upper ]; then mkdir -p /cow/upper /cow/lost+found|/cow/upper|/cow/log|/cow/crash|/cow/install-logs-*) continue ;; mv "$cow_content" /cow/upper mount -t overlay -o "upperdir=/cow/upper,lowerdir=$mounts,workdir=/cow/work" "/cow" "$rootmnt" || panic "overlay mount failed" -rw-r--r-- 1 alex alex 33834 Jun 24 2020 ./main/scripts/casper Next step I envision is to understand how /cow is created because is not see in contents of initrd