This is the RAR file format , a compressed archive that requires software like WinRAR or 7-Zip to extract. You must typically have all parts (Part1 through Part10) in the same folder to successfully rebuild the original "Full" file. Purpose of Such Conventions
Split massive files into manageable pieces (Part10) for sharing across networks or storing on physical media. mda.indiana.080.full.pl.uhd.part10.rar
Ensure that different "parts" of the same project stay together and are easily sorted chronologically or numerically. This is the RAR file format , a