The file you have—ending in .part03.rar —is a . When a file (like a high-quality PDF or a bundle of training materials) is too large for certain upload limits, it is often split into multiple chunks.
Unlocking Linux Mastery: A Guide to the Rute User’s Tutorial Rute.part03.rar
To extract the contents, you must have all parts (e.g., part01.rar , part02.rar , and part03.rar ) in the same folder. The file you have—ending in