turns out, it is old school, from 2006, back in the day. the nomenclature was such, that they first stated what kind of a roll it would be, and 4 depicts a 4 point roll, 8 depicts an 8 point roll, 2 would be a 2 point roll, then the short curved arrow, which does not cross the line, indicates it is a half roll, or anything less than a full roll.
then, after the curved arrow, there is another set of numbers, 2/4 or 4/8
which, means 2 out of 4 points in a 360 roll, which would be 180 degrees total, divided in 2, which means, rotate 90 degrees, pause, rotate 90 degrees, stop.
the 4/8, same thing: rotate 45 degrees, pause, another 45, pause, another 45, pause, and the last 45. total rotation is 180 degrees.
now, the nomenclature, which I am accustomed to seeing in the Aresti, is this:
2 x 4
or
4 x 8
best regards
Cam