Repeated from my edited post above as you replied before I posted the editI think you understand what I meant with that.Except you just said they’re a variant of the opposing roll rule - which they’re not. They don’t resemble the Opposing Roll rules at all. They’re a standard skill check made in reaction to a successful attack. They are their own thing which is why I suggest that it needs to be clarified that they’re different - a simple sentence referring to the combat chapter is sufficient to remove any ambiguity.Reaction rolls are explained in the combat section, the only place it is used and sure you could call it a special variant of the standard opposing roll rule.
For me the issue is that Chapter 3 explains how skill rolls work and provides two ways (regular skill checks and opposed rolls). The Combat chapter then adds a variation to those rules (reaction skill rolls) but doesn’t refer to whether it is a variation to the standard skill roll or the opposed rolls rules. That’s why I suggest that it needs to be clarified - a simple sentence would remove any ambiguity.