mntinfo of process

Hi, Considering the the output of #cat /proc/pid/mountinfo I have this line for one of my process 39 38 0:10 /1 /dev/console rw,relatime shared:7 - devpts devpts rw,mode=600,ptmxmode=000 Here, /1 is root: root of the mount within the filesystem.(man 5 proc) What is this /1? Thanks.