default GNOME desktop background

[Alexandros Theodotou]

I find it strange that the default background in the GNOME DE is a plain 
color instead of one of the backgrounds installed with 
gnome-backgrounds.

I am not exactly sure how to do this the guix-y way to send a patch, but 
the background that gnome uses is the value of the key "picture-uri" in 
the gsettings schema "org.gnome.desktop.background".

So, to get the background you would do:
gsettings get org.gnome.desktop.background picture-uri

To set it:
gsettings set org.gnome.desktop.background picture-uri 
"file:///home/me/Pictures/mybg.jpg"

Can we please set it to one of the pre-installed backgrounds? They can 
be found in ~/.guix_profile/share/backgrounds/gnome. How about 
adwaita-day.jpg? This is the default on most distros I believe. Or if 
someone could give me a couple of pointers how to do this I can send a 
patch. I believe one would just add a post-install command in the 
"gnome-backgrounds" package that calls `gsettings set` with the path.

--
Alex