Add .xpi support to automtime and autodescribe

Author: dfandrich

autodescribe

@@ -1424,6 +1424,14 @@ comment_xcf () {
 	fi
 }
 
+# File type: xpi (Mozilla extension)
+# requires: unzip (Info-ZIP version)
+comment_xpi () {
+	# "safe" filename guaranteed not to start with a dash
+	sf="$(safefn "$1")"
+	COMMENT=$(unzip -p "$sf" manifest.json | jq -r .name)
+}
+
 # File type: xpm (X pixmap image)
 # Could extract image size here as well
 comment_xpm () {
@@ -1794,6 +1802,9 @@ for f in "$@" ; do
 			*.xhb)
 				TYPE=xhb
 				;;
+			*.xpi)
+				TYPE=xpi
+				;;
 			*.xpm)
 				TYPE=xpm
 				;;

automtime

@@ -1098,6 +1098,16 @@ mtime_xcf_exiftool () {
 	TIME=$(echo "$RAWTIME" | sed -E -e 's/^([0-9][0-9][0-9][0-9]):([0-9][0-9]):/\1-\2-/' -e 's/([-+][0-9][0-9])(:)?([0-9][0-9])$/ \1\3/')
 }
 
+# File type: xpi (Mozilla extension)
+# requires: unzip (Info-ZIP version), openssl
+mtime_xpi () {
+    # Decode the signature rather than looking at the file mtimes since the latter
+    # seems to always be set to 1980-01-01.
+    RAWTIME=$(unzip -p "$f" META-INF/mozilla.rsa | openssl pkcs7 -print_certs -text -inform DER -in - | sed -n 's/^[[:space:]]*Not Before:[[:space:]]*//p' | head -1)
+	# $RAWTIME is like Apr 19 22:52:53 2026 GMT
+	TIME=$(normalize_time_tz "$RAWTIME")
+}
+
 # File type: zip (zip archive)
 # requires: unzip (Info-ZIP version), findutils
 mtime_zip () {
@@ -1530,6 +1540,10 @@ for f in "$@" ; do
 				TYPE=xcf
 				;;
 
+			*.xpi)
+				TYPE=xpi
+				;;
+
 			*.zpaq)
 				TYPE=zpaq
 				;;