.R2 File Extension
File TypeWinRAR Multi-Volume Archive Part 2
What is an R2 file?
Archive file that is compressed using WinRAR, a program used to create single or multi-volume archives; contains part two of a compressed volume; stores a compressed part or fragment of a larger file; may use the extensions R0 through R99.
WinRAR can create a multi-volume archive out of a large file and then build it back into the original file.