mtime=

Specify the modification time (mtime) in the gzip header. Using an Integer.

Setting the mtime in the gzip header does not effect the mtime of the file generated. Different utilities that expand the gzipped files may use the mtime header. For example the gunzip utility can use the `-N` flag which will set the resultant file’s mtime to the value in the header. By default many tools will set the mtime of the expanded file to the mtime of the gzipped file, not the mtime in the header.

If you do not set an mtime, the default value will be the time when compression started. Setting a value of 0 indicates no time stamp is available.