strange "t" before "read only" in smb.conf

[nerdoc]

I installed a fresh runeaudio, played a bit with the settings, and tried to access the samba share to load some music onto th USB stick in my RPi2.
I disabled write support at the SD share, (don't know, siwthed write support a few times on and off maybe, even on USB?)
...and rebooted.
I still couldn't create new files.

Then I saw that the /etc/samba/smb.conf file holds the following lines:

[USB]
	path = /mnt/MPD/USB
tread only = no

This should mean "read only", without the "t".

I removed the "t", restarted smb/nmb via systemctl restart - and it worked fine.

I don't know where this "t" comes from.