=== modified file 'common.zsh'
--- common.zsh	2017-11-15 16:41:23 +0000
+++ common.zsh	2017-11-15 16:33:59 +0000
@@ -2,12 +2,13 @@
 setopt no_unset warn_create_global extended_glob
 set -x
 
-typeset -g DO FILE BASE OUT FUNCDIR
+typeset -g DO FILE BASE OUT FUNCDIR META_MTIME_REF
 DO=$0
 FILE=$1
 BASE=$2
 OUT=$3
 FUNCDIR=${0:h:a}/functions
+META_MTIME_REF=
 
 # helper that prints out error message and exits
 die() {
@@ -48,6 +49,9 @@
 		arglist+=( "$k=$vars[$k]" )
 	done
 	printf >$OUT "%s" "${(j::)arglist}"
+	if [[ -n $META_MTIME_REF ]]; then
+		touch -r $META_MTIME_REF $OUT || die
+	fi
 	exit 0
 }
 

=== modified file 'default.download-file.do'
--- default.download-file.do	2017-11-15 16:41:23 +0000
+++ default.download-file.do	2017-11-15 16:33:59 +0000
@@ -10,6 +10,7 @@
 
 	wget --timestamping --force-directories --protocol-directories -P downloads $vars[url] \
 		|| die "Failed to fetch ${(qqq)vars[url]}"
+	META_MTIME_REF=$vars[filename]
 }
 . ./common.zsh
 # vim: fileencoding=utf8 ft=zsh noet sw=4 ts=4 sts=4