oohh ok, so all those entry in /usr/share/themes are not especially Themes !... sorry my bad, it was a little bit misleading..
Thanks for the hint !

Thanks for the tree command, I know it, but I was wondering if there was something that could do the ~same output out of the box.

Cheers,

Go to Settings, Notifications, and play with the Theme drop-down menu. As you select each theme, you'll see a popup notification that uses your selected theme.

The command you're looking for is 'tree'. You probably need to install it. Then run

tree /usr/share/themes

and you'll get the tree-like output you want.

Gentle reminder this is happening also on a fresh(untouched) install.

cd /usr/share/themes/

alias lsforum=ls --group-directories-first -lhA

lsforum | grep Smoke #To focus on one.
drwxr-xr-x 3 root root 4.0K Feb  7 06:37  Smoke

cd Smoke;lsforum
drwxr-xr-x 2 root root 4.0K Feb  7 06:37 xfce-notify-4.0

cd xfce-notify-4.0;lsforum
-rw-r--r-- 1 root root 610 Dec 12  2020 gtk.css

Voila, I hope it help ? (permissions seem ok to me)
Sorry I don't if out of the box there is a command to allow an output like ~

#example

755 Themes
|---- 755 Smoke
        |--- 755 xfce...
                    |--- 644 gtk.css

So on a fresh install of Devuan 4, Am I the only to have only Clearlooks-Phenix-Deepsea in the GUI Appearance ?

/usr/share/theme work (you were right) for the theme that I imported of my previous distribution !
It was a problem of files permissions

Anyway the question remain for the default themes in /usr/share/themes that do not appear in Appearance GUI

FYI: /usr/share/themes didn't work

Well it should. What _exactly_ did you try? Please supply the download URL for the themes along with the full list of exact commands used to install the theme(s).

No.

I have no idea if Xfce searches the obsolete ~/.themes location but from your post it looks like it does.

FWIW CrunchBang used to supply a compatibility symlink:

mkdir -p ~/.local/share/themes
cp -r ~/.themes/* ~/.local/share/themes/
rm -r ~/.themes
ln -s ~/.local/share/themes ~/.themes

I succeed !

Here what I've done

1- I didn't use the City_XFCE_color_pack.tar.gz but imported my own XFCE theme files from another distro from/to
/home/spongebob/.themes

FYI: /usr/share/themes didn't work

2- After having moved the files, I log off / log on (just in case).
The theme didn't appear in the GUI xfce4-appearance-settings but it appear in Window Manager I selected it then log off / log on and it applied. then ! the theme appear also in the Appearance !

Weird...

Also, to note is that in /usr/share/themes I have the following

but in Appearance was only listed by default the Clearlooks-Phenix-Deepsea

and in Window Manager only
Default
Clearlooks-Phenix-Deepsea
Daloa
Default-hdpi
Default-xhdpi
Kokodi
Moheli

I don't know if that normal ?

Cheers.

- autostart desktop files : ~/.config/autostart/
- application desktop launcher -> ~/.local/share/applications/
- backgrounds -> ~/.local/share/backgrounds/
- fonts -> ~/.local/share/fonts/
- icons -> ~/.local/share/icons/
- themes -> ~/.local/share/themes/

folders in ~ (like (~/.themes) are. deprecated).

Moreover there is the advantage to keep all your files if you install a new system and restore a backup of your home folder.

$ ls -1r /usr/share/themes/Clearlooks-Phenix-Deepsea
xfwm4
openbox-3
metacity-1
index.theme
gtk-3.0
gtk-2.0
$ ls -1r /usr/share/themes/Clearlooks-Phenix-Deepsea/xfwm4
top-right-inactive.xpm
top-right-active.xpm
top-right-active.png
top-left-inactive.xpm
top-left-active.xpm
top-left-active.png
title-5-inactive.xpm
title-5-active.xpm
title-4-inactive.xpm
title-4-active.xpm
title-3-inactive.xpm
title-3-active.xpm
title-2-inactive.xpm
title-2-active.xpm
title-1-inactive.xpm
title-1-active.xpm
themerc
right-inactive.xpm
right-active.xpm
README
png
menu-pressed.xpm
menu-inactive.xpm
menu-active.xpm
maximize-toggled-pressed.xpm
maximize-toggled-inactive.xpm
maximize-toggled-active.xpm
maximize-pressed.xpm
maximize-inactive.xpm
maximize-active.xpm
left-inactive.xpm
left-active.xpm
hide-pressed.xpm
hide-inactive.xpm
hide-active.xpm
close-pressed.xpm
close-inactive.xpm
close-active.xpm
bottom-right-inactive.xpm
bottom-right-active.xpm
bottom-left-inactive.xpm
bottom-left-active.xpm
bottom-inactive.xpm
bottom-active.xpm

The obvious thing, I would have thought, would have been to install via APT or Synaptic. The two that I can quickly find installed for me are clearlooks-phenix-deepsea-theme (Deepsea GTK3 port of Clearlooks theme; gtk3-engines-xfce is also installed, which is a GTK+-3.0 theme engine for Xfce) + gtk2-engines.

It turns out that fsmithred is the maintainer of the first one, so perhaps have a further word with him.

PS
I meant to recurse with the file listing (-R), but reverse-sorted instead (-r).

Here is what i would do via terminal.

sudo mv ~/.themes/'City XFCE emerald' /usr/share/themes/

and so on for each theme folder.

I'm running Devuan Chimaera 4.

I would like to pimp my XFCE desktop

So I've downloaded a Style (aka theme) City_XFCE_color_pack.tar.gz from https://www.xfce-look.org/p/1165653

When I click on +add (in the GUI xfce4-appearance-settings)

I select the City_XFCE_color_pack.tar.gz and I see that a folder /home/spongebob/.themes is created

but the GUI (xfce4-appearance-settings) previous screenshot remain unchanged. I've restarted the computer but it remain the same.. any ideas ?

Thanks.