Since you don't specify which you're referring to, I'm guessing you mean the hat band pattern, which seems to be vaguely similar to the link you gave.
For me, anyway, it'd be really hard to even venture a guess on what it is as there are 3 colors involved and the stitch detail isn't all that large...there are hundreds of colorwork slip-stitch patterns!
The stitch in the body of the flat piece appears to be a honeycomb stitch. One that I've done and that makes a wonderfully cushy fabric involves "knitting into the row below".
Don't know if this helps at all... :shrug: