This looks like a typo to me:

Index: src/tar.c
==================================================================
--- src/tar.c
+++ src/tar.c
@@ -607,11 +607,11 @@
 **
 ** If OUTPUTFILE is an empty string or "/dev/null" then no tarball is
 ** actually generated.  This feature can be used in combination with
 ** the --list option to get a list of the filenames that would be in the
 ** tarball had it actually been generated.  Note that --list shows only
-** filenames.  "tar tzf" shows both filesnames and subdirectory names.
+** filenames.  "tar tzf" shows both filenames and subdirectory names.
 **
 ** Options:
 **   -X|--exclude GLOBLIST   Comma-separated list of GLOBs of files to exclude
 **   --include GLOBLIST      Comma-separated list of GLOBs of files to include
 **   -l|--list               Show archive content on stdout