Well, it’s offside. Quite simple.
xg should be used to help provide context to a game though, not used as a standalone measurement, because a team can rack up xg in final 5 mins when chasing for a goal.
Like against Slovakia, the glaring chance from 50 yards is hardly a footnote on the xg, but in the context of what that chance was, it was probably best one outside of the actual goal.