The .part6.rar extension means this is the sixth piece of a larger file that was split into multiple parts to make it easier to upload or download.
If you only have part 6, you cannot open it or see the content. You must find parts 1 through 5 (and any subsequent parts) to reconstruct the file. WNDYS01WEB18.part6.rar
The prefix WNDYS01 usually refers to a specific release group or series (often associated with adult entertainment websites like Wank It Now or Wicked ), while WEB18 suggests it is a web-dl (web download) from 2018. The "Story" of the Contents WNDYS01WEB18.part6.rar