Add .oxt support to all programs

The test file type1.oxt comes from
https://extensions.libreoffice.org/en/extensions/show/21522 and is
released into the public domain by MarianSigler and by Roland Hieber
under Creative Commons CC0
https://creativecommons.org/public-domain/cc0/

autodescribe

@@ -1182,6 +1182,16 @@ comment_odf () {
 	COMMENT=$(unzip -pq "$sf" meta.xml | xmlstarlet sel -t -v /office:document-meta/office:meta/dc:title 2>/dev/null)
 }
 
+# File type: oxt (Open Document Extension)
+# requires: unzip, xmlstarlet
+comment_oxt () {
+	# "safe" filename guaranteed not to start with a dash
+	sf="$(safefn "$1")"
+	# TODO: choose the appropriate language if more than one is available
+	# instead of just using the first one
+	COMMENT=$(unzip -pq "$sf" description.xml | xmlstarlet sel -N x=http://openoffice.org/extensions/description/2006 -t -v /x:description/x:display-name/x:name -nl | head -1)
+}
+
 # File type: py (Python source code)
 comment_py () {
 	# delete #!/bin/sh line and blank comment lines
@@ -1480,6 +1490,8 @@ for f in "$@" ; do
 			# *.otf is left off because it's much more commonly a font file
 				TYPE=odf
 				;;
+			*.oxt) TYPE=oxt
+				;;
 			*.ogg) TYPE=ogg
 				;;
 			*.otf | *.ttf | *.woff) TYPE=otf

automtime

@@ -571,6 +571,7 @@ mtime_pdf () {
 
 # File type: png (PNG image)
 # requires: pngtools
+# TODO: some PNG files (e.g. written by GIMP) have a tIME chunk that could be used
 mtime_png () {
 	# "safe" filename guaranteed not to start with a dash
 	sf="$(safefn "$1")"
@@ -1196,7 +1197,7 @@ for f in "$@" ; do
 
 			*.zip | *.jar | *.xpi | *.par | *.wsz | *.wal | *.kmz | \
 			*.sxi | *.sxd | *.sxw | *.pk3 | *.ipg | *.nth | *.odt | \
-			*.ods | *.odp | *.odg | *.odf | \
+			*.ods | *.odp | *.odg | *.odf | *.oxt | \
 			*.otp | *.otg | *.ots | *.odb | *.odc | \
 			*.docx | *.epub | *.apk | *.apkm | *.war | *.xps | *.resource | \
 			*.application | *.docm | *.f3d | *.egg | *.kra | *.whl | *.3mf | \

fv

@@ -622,6 +622,7 @@ EOF
 		# Also OpenDocument Presentation Template .otp
 		# Also OpenDocument Spreadsheet Template .ots
 		# Also OpenDocument Presentation Template .otp
+		# Also OpenDocument Extension .oxt
 		# Also Quake3 packed file .pk3
 		# Also Nokia mobile phone theme .nth
 		# Also Microsoft Office Open XML document .docx
@@ -650,7 +651,7 @@ EOF
 		*.zip | *.jar | *.xpi | *.par | *.wsz | *.wal | *.kmz | \
 		*.sxi | *.sxd | *.sxw | *.sxm | *.pk3 | *.ipg | *.nth | *.odt | \
 		*.ods | *.odp | *.odg | *.odf | \
-		*.otp | *.otg | *.ots | *.odb | *.odc | \
+		*.otp | *.otg | *.ots | *.odb | *.odc | *.oxt | \
 		*.docx | *.epub | *.apk | *.apkm | *.war | *.xps | *.resource | \
 		*.application | *.docm | *.f3d | *.egg | *.kra | *.whl | *.3mf | \
 		*.sb2 | *.sb3 | *.ora | *.tc | *.wfp | *.wacz | *.xlsx | *.pptx | \

fvi

@@ -670,6 +670,7 @@ EOF
 		# Also OpenDocument Presentation Template .otp
 		# Also OpenDocument Spreadsheet Template .ots
 		# Also OpenDocument Presentation Template .otp
+		# Also OpenDocument Extension .oxt
 		# Also Quake3 packed file .pk3
 		# Also Nokia mobile phone theme .nth
 		# Also Microsoft Office Open XML .docx

test-autodescribe-expected

@@ -51,6 +51,7 @@
 'testfiles/type1.ods' 'OpenDocument Spreadsheet Title'
 'testfiles/type1.odt' 'Open Document title'
 'testfiles/type1.ogg' 'OGG artist / OGG title'
+'testfiles/type1.oxt' 'Solarized color palette'
 'testfiles/type1.pam' 'PAM comment'
 'testfiles/type1.pas' 'Pascal typical comment Not Copyright (C) 2021. Typical boilerplate goes here.'
 'testfiles/type1.patch' 'Patch subject'

test-automtime-expected

@@ -32,6 +32,7 @@
 'testfiles/type1.msg' '2021-10-12 12:34:56 +0000'
 'testfiles/type1.ods' '2021-11-06 15:45:15.657373818'
 'testfiles/type1.odt' '2021-10-13 02:28:28.386995722'
+'testfiles/type1.oxt' '2022-09-14 14:33:36'
 'testfiles/type1.patch' '2023-01-06 02:15:02 +0000'
 'testfiles/type1.pcapng' '2021-12-19 00:00:01.000000'
 'testfiles/type1.pdf' '2021-10-16 08:08:39 +0000'