Unix file Compressed
Z is a file extension for a compressed archive file used with Unix-based systems. Z file archives were commonly used when creating a compressed archive to magnetic tape for backup purposes. Z files can be opened by most current compression software, including Winzip (Windows) and Tar (Unix/Linux).
MIME type: application/x-compress, application/x-compressed, application/gzip, application/x-gzip, application/z, application/x-z
Learn more about .Z files:
Enabling/Disabling Tape Compression at ITKnowledgeExchange.com.