Is "Contents sold by weight not volume" Passive Voice or something else?
On the packaging with milk powder, I saw the remark "Contents sold by weight not volume." if it was written "is sold" everything would be clear. How can this spelling be explained? Perhaps this grammatical construction has a name
Solution 1:
"Contents sold by weight not volume." has several words missing. This is not unusual on packaging and in places where there is not a lot of space.
The full version is "The contents of this pack are sold [by the manufacturer] by weight not by volume."
It is therefore a passive.