If you have this file, do not open it. You can upload the file to VirusTotal to check for known malicious signatures without executing it on your system.
: Files with unusual double extensions are frequently used to disguise executable scripts (like .vbs or .exe ) as harmless archives.
: This is a non-standard file extension or naming suffix.
: Without a verified source or a checksum (hash), the contents of such a "collection" cannot be authenticated.
It may be a (e.g., file.zip.323.zip ) used to bypass automated security filters or indicate a multi-part (spanned) archive.