Google Voice is a great application that is available on IOS and Android. However, it is lacking a Desktop application version that could be installed on mainstream Linux and Windows (that I know of). Hence, I’ve devised this workaround to associate Google Voice as an xdg-mime type association that could be invoked while browsing Internet websites that feature clickable telephone numbers. Here are the commands for your convenience: 

# Change running context as root
sudo su

# Create a desktop file
cat << EOF > /usr/share/applications/gv-tel.desktop
[Desktop Entry]
Name=gv tel
Comment=Google Voice telephone application shortcut
Exec=bash -c 'xdg-open "https://voice.google.com/u/0/calls?a=nc,%2B${0//tel:/}"' %u
Icon=/usr/share/icons/Humanity/apps/32/vinagre.svg
Terminal=false
Type=Application
Categories=Utility
Actions=
MimeType=x-scheme-handler/tel;
EOF

# Exit root context
exit

# Change xdg-open default in the context of the current user - this is important!
xdg-mime default gv-tel.desktop x-scheme-handler/tel

# validate
xdg-mime query default x-scheme-handler/tel
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