diff --git a/share/comps-cleanup.xsl b/share/comps-cleanup.xsl
new file mode 100644
index 00000000..1fbfbdbe
--- /dev/null
+++ b/share/comps-cleanup.xsl
@@ -0,0 +1,131 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- This stylesheet will:
+     - reorder, indent and normalize a comps file,
+     - merge duplicate groups and categories,
+     - warn about packages referenced by multiple groups,
+     - kill multiple references to the same package within a group,
+
+     Typical usage is:
+     $ xsltproc -o output-file comps-cleanup.xsl original-file
+
+     You can use the ‑‑novalid xsltproc switch to kill the warning about
+     Fedora not installing the comps DTD anywhere xsltproc can find it.
+     However without DTD there is no way to check the files completely.
+
+     © Nicolas Mailhot <nim at fedoraproject dot org> 2006 -->
+<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:exsl="http://exslt.org/common" version="1.0" extension-element-prefixes="exsl">
+  <xsl:strip-space elements="*"/>
+  <xsl:output method="xml" indent="yes" encoding="UTF-8" doctype-system="comps.dtd" doctype-public="-//Red Hat, Inc.//DTD Comps info//EN"/>
+  <xsl:key name="unique-groups" match="/comps/group" use="id/text()"/>
+  <xsl:key name="unique-categories" match="/comps/category" use="id/text()"/>
+  <xsl:key name="packages-by-group" match="/comps/group/packagelist/packagereq" use="../../id/text()"/>
+  <xsl:key name="unique-package-entries" match="/comps/group/packagelist/packagereq" use="concat(../../id/text(),'/',text())"/>
+  <xsl:key name="unique-packages" match="/comps/group/packagelist/packagereq[generate-id(.) = generate-id(key('unique-package-entries',concat(../../id/text(),'/',text()))[1])]" use="text()"/>
+  <xsl:key name="groups-by-category" match="/comps/category/grouplist/groupid" use="../../id/text()"/>
+  <xsl:key name="unique-group-entries" match="/comps/category/grouplist/groupid" use="concat(../../id/text(),'/',text())"/>
+  <xsl:variable name="lcletters">abcdefghijklmnopqrstuvwxyz</xsl:variable>
+  <xsl:variable name="ucletters">ABCDEFGHIJKLMNOPQRSTUVWXYZ</xsl:variable>
+  <xsl:variable name="type-sort-order">
+    <unknown/>
+    <mandatory/>
+    <conditional/>
+    <default/>
+    <optional/>
+  </xsl:variable>
+  <xsl:variable name="attribute-sort-order">
+    <unknown/>
+    <type/>
+    <requires/>
+    <basearch/>
+  </xsl:variable>
+<!-- Preserve most nodes -->
+  <xsl:template match="*" priority="0">
+    <xsl:apply-templates select="." mode="normalize"/>
+  </xsl:template>
+  <xsl:template match="*" mode="normalize">
+<!-- Group comments with the logically-following element -->
+    <xsl:apply-templates select="preceding-sibling::node()[normalize-space()][1][self::comment()] "/>
+    <xsl:copy>
+      <xsl:apply-templates select="@*">
+        <xsl:sort select="count(exsl:node-set($attribute-sort-order)/*[name() = name(current())]/preceding-sibling::*)" data-type="number"/>
+      </xsl:apply-templates>
+      <xsl:apply-templates select="*|text()"/>
+    </xsl:copy>
+  </xsl:template>
+<!-- Preserve attributes and text nodes -->
+  <xsl:template match="comment()|text()">
+    <xsl:apply-templates select="preceding-sibling::node()[normalize-space()][1][self::comment()] "/>
+    <xsl:copy/>
+  </xsl:template>
+<!-- Preserve attributes -->
+  <xsl:template match="@*">
+    <xsl:copy/>
+  </xsl:template>
+<!-- Sort groups by id, and categories by display order -->
+  <xsl:template match="comps" priority="1">
+    <xsl:apply-templates select="preceding-sibling::node()[normalize-space()][1][self::comment()] "/>
+    <xsl:copy>
+      <xsl:apply-templates select="group">
+        <xsl:sort select="translate(id/text(),$lcletters,$ucletters)"/>
+      </xsl:apply-templates>
+      <xsl:apply-templates select="category">
+        <xsl:sort select="display_order/text()"/>
+        <xsl:sort select="translate(id/text(),$lcletters,$ucletters)"/>
+      </xsl:apply-templates>
+    </xsl:copy>
+  </xsl:template>
+<!-- Warn about empty groups -->
+  <xsl:template match="group[count(key('packages-by-group',id/text()))=0]" priority="2">
+    <xsl:message>☹☹☹ Empty group <xsl:value-of select="concat(_name/text(),' (',id/text(),')')"/>!</xsl:message>
+    <xsl:apply-templates select="." mode="normalize"/>
+  </xsl:template>
+<!-- Warn about duplicate groups being merged -->
+  <xsl:template match="group[generate-id(.) != generate-id(key('unique-groups',id/text())[1])]" priority="3">
+    <xsl:message> ☹☹ Duplicate group <xsl:value-of select="concat(_name/text(),' (',id/text(),')')"/> will be merged.</xsl:message>
+  </xsl:template>
+<!-- Warn about empty categories -->
+  <xsl:template match="category[count(key('groups-by-category',id/text()))=0]" priority="2">
+    <xsl:message>☹☹☹ Empty category <xsl:value-of select="concat(_name/text(),' (',id/text(),')')"/>!</xsl:message>
+    <xsl:apply-templates select="." mode="normalize"/>
+  </xsl:template>
+<!-- Warn about duplicate categories being merged -->
+  <xsl:template match="category[generate-id(.) != generate-id(key('unique-categories',id/text())[1])]" priority="3">
+    <xsl:message> ☹☹ Duplicate category <xsl:value-of select="concat(_name/text(),' (',id/text(),')')"/> will be merged.</xsl:message>
+  </xsl:template>
+<!-- Sort packages within a group by class then name -->
+  <xsl:template match="packagelist" priority="1">
+    <xsl:copy>
+      <xsl:apply-templates select="key('packages-by-group',../id/text())">
+        <xsl:sort select="count(exsl:node-set($type-sort-order)/*[name() = current()/@type]/preceding-sibling::*)" data-type="number"/>
+        <xsl:sort select="translate(text(),$lcletters,$ucletters)"/>
+      </xsl:apply-templates>
+    </xsl:copy>
+  </xsl:template>
+<!-- Sort groups within a category by name -->
+  <xsl:template match="category/grouplist" priority="1">
+    <xsl:copy>
+      <xsl:apply-templates select="key('groups-by-category',../id/text())">
+        <xsl:sort select="translate(text(),$lcletters,$ucletters)"/>
+      </xsl:apply-templates>
+    </xsl:copy>
+  </xsl:template>
+<!-- Kill duplicate package entries -->
+  <xsl:template match="packagereq[generate-id(.) != generate-id(key('unique-package-entries',concat(../../id/text(),'/',text()))[1])]" priority="2">
+    <xsl:message>☹☹☹ Ignoring duplicate reference to <xsl:value-of select="concat(@type,' package ',text())"/> in group <xsl:value-of select="concat(../../_name/text(),' (',../../id/text(),')')"/>.</xsl:message>
+    <xsl:message>     ⇒ Only its first reference (<xsl:value-of select="key('unique-package-entries',concat(../../id/text(),'/',text()))[1]/@type"/> package) will be kept.</xsl:message>
+  </xsl:template>
+<!-- Kill duplicate group entries -->
+  <xsl:template match="category/grouplist/groupid[generate-id(.) != generate-id(key('unique-group-entries',concat(../../id/text(),'/',text()))[1])]" priority="1">
+    <xsl:message>  ☹ Ignoring duplicate reference to group <xsl:value-of select="text()"/> in category <xsl:value-of select="concat(../../_name/text(),' (',../../id/text(),')')"/>.</xsl:message>
+  </xsl:template>
+<!-- Warn about packages referenced several times -->
+  <xsl:template match="packagereq[generate-id(.) = generate-id(key('unique-packages',text())[2])]" priority="1">
+    <xsl:variable name="dupes" select="key('unique-packages',text())"/>
+    <xsl:message>  ☹ Package <xsl:value-of select="text()"/> is referenced in <xsl:value-of select="count($dupes)"/> groups:</xsl:message>
+    <xsl:for-each select="$dupes">
+      <xsl:sort select="translate(../../id/text(),$lcletters,$ucletters)"/>
+      <xsl:message>     ✓ <xsl:value-of select="@type"/> package in group <xsl:value-of select="concat(../../_name/text(),' (',../../id/text(),')')"/></xsl:message>
+    </xsl:for-each>
+    <xsl:apply-templates select="." mode="normalize"/>
+  </xsl:template>
+</xsl:stylesheet>