On the XFR snowbike rear suspension there is a set of holes just in front of the forward suspension arm. These holes are intended for this set of Ice Scratchers.
If you ride on hard pack trails, a set of ice scratchers are necessary to save your hi-fax and will make them last. When a hi-fax runs dry from lack of snow lubrication, the friction will heat up the clips on the track and will begin to melt the hi-fax. This can cause them to wear out quickly. The ice scratchers kick up snow and ice to keep the hi-fax and clips cool and wet in hardpack conditions.