The file appears to be a 7-Zip compressed archive, likely named "si" (possibly for System Information or Silent Installation ). Based on your mention of "long content," you are likely dealing with high compression levels, large file sizes, or complex directory paths that can cause performance issues or extraction errors. Common Issues with Large .7z Files
: If the archive is "long" and was interrupted during creation, the headers (stored at the end of the file) may be missing or corrupt. Key Technical Specs Unable to extract 7z archives with long paths #116 - GitHub The file appears to be a 7-Zip compressed
: Using "Ultra" compression on large files requires significant RAM (sometimes over 8GB for a 512MB dictionary). large file sizes