clarify xyz.openbmc_project.Software.Version usage

There were some implied assumptions that were not documented properly
with this interface. openbmc/bmcweb#109 is a result of that lack of
clarity.

https://gerrit.openbmc-project.xyz/c/openbmc/bmcweb/+/28238 will ensure
this is implemented within bmcweb.

Change-Id: Idc3ffa2964920a78c7f387d6cc77375c16d64248
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
diff --git a/xyz/openbmc_project/Software/Version.interface.yaml b/xyz/openbmc_project/Software/Version.interface.yaml
index e769bf7..345e5b5 100644
--- a/xyz/openbmc_project/Software/Version.interface.yaml
+++ b/xyz/openbmc_project/Software/Version.interface.yaml
@@ -1,5 +1,10 @@
 description: >
-    Simple definition of a Software or Firmware version.
+    Simple definition of a Software or Firmware version. Note that this
+    interface may be implemented by D-Bus objects that do not necessarily
+    contain a software level. For example an OpenBMC log may implement this
+    interface to store the software level of the BMC or Host for debug purposes.
+    If looking for real software versions associated with a device then ensure
+    this interface is under the /xyz/openbmc_project/software object path.
 properties:
     - name: Version
       type: string