etc/xbps.conf: sync with reality.

etc/xbps.conf

@@ -15,6 +15,9 @@
 
 ## REPOSITORIES
 #
+# The `repository' keyword defines a repository. A complete URL or absolute
+# path to a local directory can be used.
+#
 # The default system repository directory "<rootdir>/usr/share/xbps/repo.d"
 # contains the system repository configuration files.
 #
@@ -29,14 +32,20 @@
 #    the <arch>-repodata file.
 #  - Accepted protocols for remote repositories: ftp, http or https.
 #  - Repositories are added in the order in which are specified (top->bottom).
+#  - Repositories declared in this file are added at the head of the list.
+#  - Repositories declared in the system or configuration directories are added
+#    to the tail of the list.
 #
 # The "repository" keyword can be used to include additional repositories in
 # addition to the files available in /etc/xbps/repo.d/*.conf and
 # /usr/share/xbps/repo.d/*.conf.
 #
-#repository=<url>
+# Example:
+#	repository=http://foo.example.org/dir
+#	repository=https://foo.example.org:8080/dir
+#	repository=/hostdir/binpkgs
 
-# REPOSITORY MIRRORS
+## REPOSITORY MIRRORS
 #
 # - http://repo2.voidlinux.eu/current
 # - http://repo2.voidlinux.eu/current/nonfree
@@ -50,6 +59,22 @@
 # - http://repo3.voidlinux.eu/current/multilib/nonfree
 # - http://repo3.voidlinux.eu/current/debug
 
+## PRESERVING FILES
+#
+# The `preserve` keyword can be used to make xbps ignore changes to the
+# specified files. Files must be specified with absolute pathnames or via
+# file globbing.
+#
+# The system preserve directory is set to <rootdir>/usr/share/xbps/preserve.d.
+# The configuration preserve directory is set to <rootdir>/etc/xbps/virtualpkg.d.
+#
+# Files bearing the same name in the configuration directory override the
+# ones from the system directory.
+#
+# Example:
+#	preserve=/etc/file
+#	preserve=/etc/dir/*.conf
+
 ## VIRTUAL PACKAGES
 #
 # Virtual package overrides. You can set your own list of preferred virtual