Snap built apps

Unfortunately the snap-built apps are not supported almost by any icons themes, because the icons are hardcoded and the desktop files are not hosted in the folder ~/.local/share/applications or /usr/share/applications.

To solve it, please follow the instructions:

1. Do:

# Copy all desktop files of all snap-built apps to "~/.local/share/applications"
sudo cp /var/lib/snapd/desktop/applications/*.desktop ~/.local/share/applications
# To make the files publically accessible
sudo chmod -R 777 ~/.local/share/applications
# To remove the duplicates
sudo rm /var/lib/snapd/desktop/applications/*.desktop

2. Go to the directory ~/.local/share/applications;
3. Open each desktop file of snap app with your favourite text editor and modify the encoded path of Icon to the simple path with no extension. For example, if you use Insomnia:

# Replace...
Icon=snap/icons/icon.png
# for
Icon=insomnia

4. Run update-desktop-database in the terminal.