Do you have of this archive, or are you seeing an error message when trying to open it?

It significantly reduces the size of the archive, especially when compressing many similar files.

Solid compression is a 7-Zip feature that treats multiple files within the archive as one continuous data stream.

Since this is part 3 of a set, you cannot open it by itself. To extract the contents:

When you see a file ending in , it means it is the third piece of a larger split archive. The mention of a "solid feature" (Solid Compression) is a specific method used by 7-Zip to improve the compression ratio. Understanding Solid Compression