Description of problem:
Xfce spin is using the upstream desktop background in F31.
Version-Release number of selected component (if applicable):
I thought it would be as easy as:
diff --git a/xfdesktop.spec b/xfdesktop.spec
index 0fa406f..6a44e6f 100644
@@ -2,7 +2,7 @@
Summary: Desktop manager for the Xfce Desktop Environment
@@ -39,7 +39,7 @@ This package includes a desktop manager for the Xfce Desktop Environment.
# change default background for Fedora
-sed -i 's/\/backgrounds\/xfce\/xfce-teal.jpg/\/backgrounds\/images\/default.png/g' common/xfdesktop-common.h
+sed -i 's/\/backgrounds\/xfce\/xfce-stripes.png/\/backgrounds\/images\/default.png/g' common/xfdesktop-common.h
@@ -69,6 +69,9 @@ desktop-file-validate \
+* Thu Sep 12 2019 Kevin Fenzi <kevin> - 4.14.1-2
+- Fix the default background. Upstream changed default, we need to adjust our change.
* Mon Aug 12 2019 Mukundan Ragavan <nonamedotc> - 4.14.1-1
- Update to 4.14.1
But that didn't seem to do it. Will investigate more.
+1 Final blocker.
why would you escape all those slashes and not just use a different separator for the sed command :P
I didn't write the orig sed there, was just modifying it, but sure could do that.
(but note that the sed change works, I am not sure why it's not defaulting properly after that).
FEDORA-2019-ff99c07a62 has been submitted as an update to Fedora 31. https://bodhi.fedoraproject.org/updates/FEDORA-2019-ff99c07a62
So, this really does fix things in my testing, so I am going to push it for more feedback.
Note: The first time you login your user would get a local to them xfconf entry with the default background. So, if you logged in at anytime with a user it may well have the OLD wrong background.
So, this should be tested with either a fresh install, or at least a fresh user.
xfdesktop-4.14.1-2.fc31 has been pushed to the Fedora 31 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2019-ff99c07a62
Discussed during the 2019-09-16 blocker review meeting: 
The decision to classify this bug as an "AcceptedBlocker" was made as it violates the following criterion:
"The proposed final Fedora artwork must be included and used as the background on release-blocking desktops..."
xfdesktop-4.14.1-2.fc31 fixes the default wallpaper for new users.
xfdesktop-4.14.1-2.fc31 has been pushed to the Fedora 31 stable repository. If problems still persist, please make note of it in this bug report.