Reason why "nocache" option is not displayed in "mount"?

Hi,

what is the reason why "nocache" is not displayed in the output of 
"mount" for nullfs options?

# grep packages /etc/fstab.commit_leidinger_net
/shared/ports/packages          
/space/jails/commit.leidinger.net/shared/ports/packages         nullfs  
rw,noatime,nocache      0 0

# mount | grep commit | grep packages
/shared/ports/packages on 
/space/jails/commit.leidinger.net/shared/ports/packages (nullfs, local, 
noatime, noexec, nosuid, nfsv4acls)

Context: I wanted to check if poudriere is mounting with or without 
"nocache", and instead of reading the source I wanted to do it more 
quickly by looking at the mount options.

Bye,
Alexander.

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