why?
.... Upgrade 8 Packages .... Total download size: 5.7 M Downloading Packages: Setting up and reading Presto delta metadata updates/prestodelta | 1.1 MB 00:00 Processing delta metadata Download delta size: 553 k .... Finishing rebuild of rpms, from deltarpms <locally rebuilding deltarpms> | 3.5 MB 00:03 Presto reduced the update size by 85% (from 3.5 M to 553 k). ....