Which units are shown in the display of the support reactions (kN or kN/m)?
The graphic provides no information.
In case the support reactions are given in kN/m, for which distance does the value apply?
You can see the unit of the nodal and line supports in the Max/Min info.
For the support reactions, for example, the units kN/m and for the support moment kNm/m are used.
In the graphic, this is not indicated by default, because results of internal forces can also be shown in the graphic. You can activate the output of the units in the Display navigator under "Results" -> "Result Values."
A value refers to a distance of 1 m.
A partial value is shown in each FE mesh node.
This allows for a snapshot of the line support, as it were.