Add metainfo supports as plug-ins

All debian-reference-<lang> packages are extension packages of
debian-reference-common.

Closes: #1110857

.gitignore

@@ -26,5 +26,6 @@ packages.stable.txt
 packages.txt
 pkg.lst
 templates.pot
+org.debian.debian-reference-*.metainfo.xml
 tmp
 

debian/all.install-in

@@ -1,3 +1,4 @@
 build/debian-reference.@@.txt.gz usr/share/doc/debian-reference-common/docs
 build/debian-reference.@@.pdf usr/share/doc/debian-reference-common/docs
 build/*.@@.html usr/share/doc/debian-reference-common/docs
+org.debian.debian-reference-@@.metainfo.xml usr/share/metainfo

debian/all.metainfo-in

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- Copyright 2026 Osamu Aoki <osamu@debian.org> -->
+<component type="addon">
+  <id>org.debian.debian-reference-@@</id>
+  <extends>debian-reference-common.desktop</extends>
+  <name>Debian Reference (@LANG@)</name>
+  <summary>Debian system administration guide, @LANG@ document</summary>
+  <metadata_license>CC0-1.0</metadata_license>
+  <project_license>GPL-2.0+</project_license>
+  <url type="homepage">https://www.debian.org/doc/user-manuals#quick-reference</url>
+</component>

debian/rules

@@ -57,6 +57,7 @@ override_dh_auto_build:
 	  sed  -e "s/@@/$$XX/g" < all.install-in  >$(MANUAL)-$${XX}.install ; \
 	  sed  -e "s/@@/$$XX/g" < all.links-in  >$(MANUAL)-$${XX}.links ; \
 	  sed  -e "s/@@/$$XX/g" -e "s/@LANG@/$$LANGX/g" < all.doc-base-in  >$(MANUAL)-$${XX}.doc-base ; \
+	  sed  -e "s/@@/$$XX/g" -e "s/@LANG@/$$LANGX/g" < all.metainfo-in  >$(CURDIR)/org.debian.$(MANUAL)-$${XX}.metainfo.xml ; \
 	done
 	dh_auto_build $(BUILDOPT) -- \
 		"LANGALL=$(LANGALL)" \