Apps installed via Snap

Unfortunately the Snap apps are not supported almost by any icons themes, because the icons paths of apps installed via Snap are hardcoded and their 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 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 hardcoded 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

1. Run the command update-desktop-database in the terminal to refresh the list of desktop files.