Every dot is shown, so two side-by-side cells with no dot between them are neither one apart nor one double the other. That rules digits out as surely as a dot does.
A digit goes from a cell when everything left in the cell beside it, across an edge with no dot, is one apart from it, double it or half it. The fewer candidates the neighbour has, the more this finds.
Worked examples
2 positions from real Kropki puzzles on this site, the familiar case first. Step through each one: the board lights what each step talks about, and the arrows show what rules what out.
No dot between them
There is no dot on the lit edge, so these two digits are not one apart, and neither is double the other.
Both cells lose a digit
No dot on the lit edge, and both cells have only a few candidates left: each one limits the other.
Where it fits
MediumNo Dot is a Medium technique: Medium Kropki puzzles are the first to need it.
The Kropki overview explains the rule and the levels.
Try it on a Medium Kropki puzzle. Next Step points it out when it is the move.