# This is all of the non·asset, nonrecursive files.
 override compilablefiles := $(filter-out $(assetfiles) $(recursivefiles),$(sourcefiles))
 
+ifneq ($(wildcard $(BUILDDIR)/destinations),)
+# Get the output of the destination transform.
+override destinations := $(shell $(CAT) $(BUILDDIR)/destinations)
+
+# Pair source files and their destinations.
+override sourcedestinationpair := $(foreach destination,$(destinations),$(call sourcefile,$(firstword $(subst |, ,$(destination))))|$(call perdec,$(subst $(space),|,$(wordlist 2,$(words $(subst |, ,$(destination))),$(subst |, ,$(destination))))))
+
+# (callable) Get the destination for the given source files.
+override destination = $(foreach file,$1,$(patsubst $(file)|%,%,$(filter $(file)|%,$(sourcedestinationpair))))
+
 # Pair each source file and include with its compiled location.
-override sourcecompiledpair := $(foreach file,$(sourcefiles) $(sourceincludes),$(file)|$(BUILDDIR)/public/$(call sourcepath,$(file)))
+override sourcecompiledpair := $(foreach file,$(sourcefiles) $(sourceincludes),$(file)|$(BUILDDIR)/public/$(call destination,$(file)))
 
 # (callable) Get the location of the transformed X·M·L files for the
 # given source files.
 override uncompiled = $(foreach file,$1,$(patsubst %|$(file),%,$(filter %|$(file),$(sourcecompiledpair))))
 
 # (callable) Get the installed locations for the given source files.
-override installed = $(foreach file,$1,$(DESTDIR)/$(call sourcepath,$(file)))
+override installed = $(foreach file,$1,$(DESTDIR)/$(call destination,$(file)))
+endif
 
 # ─ ¶ Recipe Variable Definitions ─────────────────────────────────────
 
 
 # List all source files and includes and their computed types.
 list:
-       $(silent)$(PRINTF) '%b' $(call quote,$(foreach file,$(sort $(sourcefiles)) $(sort $(sourceincludes)),\0033[1m$(file)\0033[22m|$(call typeoffile,$(file))|[\0033[3m$(if $(filter $(file),$(xmlfiles)),xml,$(if $(filter $(file),$(plaintextfiles)),text,asset))$(if $(filter $(file),$(sourceincludes)),|include,)\0033[23m]$(if $(call dependencies,$(file))$(call recursives,$(file)), $(strip $(foreach recursive,$(call recursives,$(file)),\0033[93;41m•|Recursive|Dependency|\0033[39;49m|$(recursive)) $(foreach dependency,$(call dependencies,$(file)),\0033[2m•|Dependency|\0033[22m|$(dependency)))) )) | $(TR) ' |' '\n '
+       $(silent)$(PRINTF) '%b' $(call quote,$(foreach file,$(sort $(sourcefiles)) $(sort $(sourceincludes)),\0033[1m$(file)\0033[22m|$(call typeoffile,$(file))|[\0033[3m$(if $(filter $(file),$(xmlfiles)),xml,$(if $(filter $(file),$(plaintextfiles)),text,asset))$(if $(filter $(file),$(sourceincludes)),|include,)\0033[23m]$(if $(call dependencies,$(file))$(call recursives,$(file)), $(strip $(foreach recursive,$(call recursives,$(file)),\0033[93;41m•|Recursive|Dependency|\0033[39;49m|$(recursive)) $(foreach dependency,$(call dependencies,$(file)),\0033[2m•|Dependency|\0033[22m|$(dependency))))$(if $(filter $(file),$(sourcefiles)), →|<\0033[4m/$(call destination,$(file))\0033[24m>,) )) | $(TR) ' |' '\n '
 
 # Raise an error when attempting to build any files with recursive
 # dependencies.
 #
 # This recipe only exists after types have been updated or when the
 # dependency graph already exists.
-$(THISDIR)/GNUmakefile:: $(BUILDDIR)/dependencies
+$(THISDIR)/GNUmakefile:: $(BUILDDIR)/dependencies $(BUILDDIR)/destinations
        $(silent)$(TOUCH) $(THISDIR)/GNUmakefile
        $(silent)$(RM) -f $(BUILDDIR)/.update-types
-       @$(PRINTF) '%b\n' '\0033[1mDependency graph updated. Restarting…\0033[22m'
+       @$(PRINTF) '%b\n' '\0033[1mDependency graph and output destinations updated. Restarting…\0033[22m'
 endif
 
 ifeq ($(wildcard $(BUILDDIR)/.update-types),)
        @$(ECHO) "Identifying dependencies…"
        $(silent)$(XSLTPROC) -o $(call quote,$@) $(call quote,$(THISDIR)/lib/catalog2dependencies.xslt) $(call quote,$<)
 
+# Generate a catalog of destinations for files. This depends on parsing
+# non·asset source files, but not assets or includes. It does not
+# require knowing the dependencies.
+$(BUILDDIR)/destinations: $(BUILDDIR)/catalog $(call parsed,$(filter-out $(assetfiles),$(sourcefiles))) $(THISDIR)/lib/catalog2destinations.xslt
+       @$(ECHO) "Identifying output destinations…"
+       $(silent)$(XSLTPROC) -o $(call quote,$@) $(call quote,$(THISDIR)/lib/catalog2destinations.xslt) $(call quote,$<)
+
 # Generate the main transform.
 $(BUILDDIR)/transform.catalog: $(TRANSFORMS)
        @$(ECHO) "Generating catalog of transforms…"
 
--- /dev/null
+<?xml version="1.0"?>
+<!--
+⁌ ⛩️📰 书社 ∷ lib/catalog2destinations.xslt
+
+© 2024 Lady [@ Lady’s Computer]
+
+This Source Code Form is subject to the terms of the Mozilla Public License, v 2.0.
+If a copy of the M·P·L was not distributed with this file, You can obtain one at <https://mozilla.org/MPL/2.0/>.
+-->
+<transform
+       xmlns="http://www.w3.org/1999/XSL/Transform"
+       xmlns:catalog="urn:oasis:names:tc:entity:xmlns:xml:catalog"
+       xmlns:书社="urn:fdc:ladys.computer:20231231:Shu1She4"
+       version="1.0"
+>
+       <template match="/">
+               <for-each select="//catalog:uri[starts-with(@name, 'about:shushe?source=')]">
+                       <choose>
+                               <when test="substring-after(@uri, '#')='xml'">
+                                       <variable name="destination" select="document(substring-before(@uri, '#'), .)/*/@书社:destination"/>
+                                       <value-of select="@name"/>
+                                       <text>|</text>
+                                       <choose>
+                                               <when test="$destination">
+                                                       <value-of select="$destination"/>
+                                               </when>
+                                               <otherwise>
+                                                       <value-of select="substring-after(@name, 'about:shushe?source=')"/>
+                                               </otherwise>
+                                       </choose>
+                                       <text>
</text>
+                               </when>
+                               <otherwise>
+                                       <value-of select="@name"/>
+                                       <text>|</text>
+                                       <value-of select="substring-after(@name, 'about:shushe?source=')"/>
+                                       <text>
</text>
+                               </otherwise>
+                       </choose>
+               </for-each>
+       </template>
+       <output method="text" encoding="UTF-8"/>
+</transform>