notification-timeout is a Gnome Shell extension that allows configuring the same timeout for all notifications. It also allows ignoring the idle state, which means all the notification can timeout even if the system is idle.
This extension supports Gnome Shell verison 45 and above.
https://extensions.gnome.org/extension/3795/notification-timeout/
git clone https://github.com/vchlum/notification-timeout.gitcd notification-timeoutmake buildmake install- Log out & Log in
gnome-extensions enable notification-timeout@chlumskyvaclav.gmail.com
- These are only required to install from source
makegnome-shell(gnome-extensionscommand)