Here it is:
root@lxc2~# mount | grep tmpfs
none on /dev type tmpfs (rw,relatime,size=492k,mode=755,uid=100000,gid=100000,inode64)
udev on /dev/full type devtmpfs (rw,nosuid,relatime,size=528326268k,nr_inodes=132081567,mode=755,inode64)
udev on /dev/null type devtmpfs...