What aspect of the structure of the alkene does ozonolysis not tell you?
Ozonolysis does not tell you about any stereochemistry there may have been in the original alkene.
Reductive ozonolysis converts an alkene into a pair of carbonyl compounds.
If the R groups are different, we can have cis/trans or E/Z stereochemistry.
If R₂ and R₄ are the groups with higher priority, 1 is a Z alkene. 2 is an E alkene.
But both give the same ozonolysis products.
You cannot distinguish between cis-but-2-ene and trans-but-2-ene by reductive ozonolysis.
They both give acetaldehyde as the only ozonolysis product.