Yaru theme

Build from source

sudo apt install meson sassc pkg-config libglib2.0-dev

cd $HOME
git clone [email protected]:ubuntu/yaru.git
cd yaru
mkdir xyz $HOME/YaruBuiltFromSource
meson setup --prefix=$HOME/YaruBuiltFromSource xyz
ninja -C xyz
ninja -C xyz install

Copy $HOME/YaruBuiltFromSource/share into /usr/local/share or https://github.com/ubuntu/yaru/blob/master/CONTRIBUTING.md#build-deb-files-from-source

#Inside yaru directory
cd yaru
#Building binary debian files
dpkg-buildpackage --build=binary -uc -us -tc
#Leaving yaru directory
cd ..
#Installing all generated .deb(s)
sudo dpkg -i yaru-theme-*.deb

Flatpak

Install Flatseal
Add ~/.themes to the Other files sections, this will allow all applications to access this folder.
Copy the theme folder from /usr/share/themes/Yaru-blue-dark to ~/.themes/Yaru-blue-dark.
Delete the broken ~/.themes/Yaru-blue-dark/gnome-shell.
Create a new folder ~/.themes/Yaru-blue-dark/gnome-shell.
Copy icons from /usr/share/gnome-shell/theme/Yaru-blue-dark into ~/.themes/Yaru-blue-dark/gnome-shell.
Back on Flatseal, add GTK_THEME=Yaru-blue-dark as a Variable. This variable will be applied to all applications and tell them to use Yaru-blue-dark.

brccabral/01_README.md

Yaru theme

Flatpak