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+.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
+
+Using an External SCM
+*********************
+
+If you're working on a recipe that pulls from an external Source Code
+Manager (SCM), it is possible to have the OpenEmbedded build system
+notice new recipe changes added to the SCM and then build the resulting
+packages that depend on the new recipes by using the latest versions.
+This only works for SCMs from which it is possible to get a sensible
+revision number for changes. Currently, you can do this with Apache
+Subversion (SVN), Git, and Bazaar (BZR) repositories.
+
+To enable this behavior, the :term:`PV` of
+the recipe needs to reference
+:term:`SRCPV`. Here is an example::
+
+   PV = "1.2.3+git${SRCPV}"
+
+Then, you can add the following to your
+``local.conf``::
+
+   SRCREV:pn-PN = "${AUTOREV}"
+
+:term:`PN` is the name of the recipe for
+which you want to enable automatic source revision updating.
+
+If you do not want to update your local configuration file, you can add
+the following directly to the recipe to finish enabling the feature::
+
+   SRCREV = "${AUTOREV}"
+
+The Yocto Project provides a distribution named ``poky-bleeding``, whose
+configuration file contains the line::
+
+   require conf/distro/include/poky-floating-revisions.inc
+
+This line pulls in the
+listed include file that contains numerous lines of exactly that form::
+
+   #SRCREV:pn-opkg-native ?= "${AUTOREV}"
+   #SRCREV:pn-opkg-sdk ?= "${AUTOREV}"
+   #SRCREV:pn-opkg ?= "${AUTOREV}"
+   #SRCREV:pn-opkg-utils-native ?= "${AUTOREV}"
+   #SRCREV:pn-opkg-utils ?= "${AUTOREV}"
+   SRCREV:pn-gconf-dbus ?= "${AUTOREV}"
+   SRCREV:pn-matchbox-common ?= "${AUTOREV}"
+   SRCREV:pn-matchbox-config-gtk ?= "${AUTOREV}"
+   SRCREV:pn-matchbox-desktop ?= "${AUTOREV}"
+   SRCREV:pn-matchbox-keyboard ?= "${AUTOREV}"
+   SRCREV:pn-matchbox-panel-2 ?= "${AUTOREV}"
+   SRCREV:pn-matchbox-themes-extra ?= "${AUTOREV}"
+   SRCREV:pn-matchbox-terminal ?= "${AUTOREV}"
+   SRCREV:pn-matchbox-wm ?= "${AUTOREV}"
+   SRCREV:pn-settings-daemon ?= "${AUTOREV}"
+   SRCREV:pn-screenshot ?= "${AUTOREV}"
+   . . .
+
+These lines allow you to
+experiment with building a distribution that tracks the latest
+development source for numerous packages.
+
+.. note::
+
+   The ``poky-bleeding`` distribution is not tested on a regular basis. Keep
+   this in mind if you use it.
+