A repack version of a driver typically implies that the original driver package has been re-created or re-packaged, often to include additional features, updates, or fixes not present in the original release.
An SPD (Spreadtrum) driver is a software component that enables communication between a computer and a device powered by a Spreadtrum chipset. Spreadtrum is a Chinese fabless semiconductor company that produces chipsets for various mobile devices.
The R420 SPD driver is a specific driver designed for devices using the Spreadtrum R420 chipset. This chipset is commonly used in entry-level and mid-range smartphones and tablets.