nothing 
As an experiment: close PL, create a new folder and copy this JPEG and its DOP file, as well as a renamed version of the same JPEG, there.
Open this new folder in PL and compare both JPEGs – no difference, they are identical.
.
Well, there is a purpose …
→ If you don’t preset your RGB images to “No Correction”, but …
your unaccompanied & newly discovered JPEG can look different → see … .