Always right-click on Part 1 and select "Extract Here." The software (WinRAR or 7-Zip) will automatically pull the data from Part 2 to complete the file. Which direction were you hoping to go with this?

Since your query also mentions it’s a bit ambiguous. Depending on what you need, I can help in two ways:

Argue whether these files represent a form of "digital archaeology" or simple copyright infringement.