dpkg-deb(1): Clarify the default compression-levels

debian/changelog

@@ -191,6 +191,7 @@ dpkg (1.16.1) UNRELEASED; urgency=low
     been fsync()ed and cannot be executed causing ETXTBSY when trying
     to open the to be installed paths for writing.
     Thanks to Jonathan Nieder <jrnieder@gmail.com>. Closes: #635683
+  * Clarify the default dpkg-deb compression-levels on the man page.
 
   [ Updated dpkg translations ]
   * German (Sven Joachim). Closes: #620312

man/dpkg-deb.1

@@ -195,8 +195,8 @@ explanation of the \fB\-\-showformat\fP option in
 The default for this field is "${Package}\\t${Version}\\n".
 .TP
 .BI \-z compress-level
-Specify which compression level to pass to the compressor backend program,
-when building a package.
+Specify which compression level to use on the compressor backend, when
+building a package (default is 9 for gzip and bzip2, 6 for xz and lzma).
 .TP
 .BI \-Z compress-type
 Specify which compression type to use when building a package. Allowed