This is a proprietary archive format developed by Eugene Roshal. You will need software like WinRAR , 7-Zip , or The Unarchiver to extract the contents.
To provide a more detailed write-up, checking the following would be helpful:
In many educational contexts, "KS4" refers to Key Stage 4 , the legal term for the two years of school education which incorporate GCSEs in England, Wales, and Northern Ireland. The "SP15" might denote "Spring 2015" or "Specimen Paper 15."
Larger archives often indicate media or software, while small ones typically contain text documents or code.
It may also represent a specific project phase, such as "Knowledge Sharing 4, Sprint 15." Technical Details