This signifies that the file is a "split volume." Because high-definition video files are often several gigabytes in size, uploaders split them into smaller, more manageable pieces (e.g., 500MB or 1GB each) to make uploading and downloading more reliable.

Tools like WinRAR , 7-Zip , or The Unarchiver are used to "extract" the data.

This is the file extension for a WinRAR compressed archive. How Split RAR Archives Work

Given the name "Panther," this is often associated with high-quality bootlegs or official concert films of the heavy metal band Pantera , specifically remastered "HD" versions of older VHS or DVD releases. Risks and Considerations