Add incremental updates to the PWNd password data sets
While it wouldn't preserve order, generally, it would greatly reduce the burden on people downloading those data sets for their own use. It has the potential to drastically reduce the bandwidth costs for the system as users would likely download the bulk of the set just once and then get the updates thereafter.
This isn’t feasible as each incremental update doesn’t just add new passwords, it updates the counts on existing ones too. Better just to use the k-anonymity API.