Here’s a simple Gnome Shell plugin to make your windows semi transparent on movement or resizing the window size. So, you can have a quick peek of the background when you move any window over the desktop and even between different workspaces.
Download Transparent Window Moving Gnome Shell Extension
If you already have Gnome Shell integration on your Linux distribution and the web browser. You could use the toggle button to activate the extension. Make sure you check the settings menu of the extension to adjust the level of transparency in Gnome Tweak Tools. Also, you could set the transperancy option on window movement and resizing or both.
How To install Gnome Tweak Tool
Ubuntu, Linux Mint, Debian based.
apt-get install gnome-tweak-tool
dnf install gnome-tweak-tool
RHEL / CentOS
yum install gnome-tweak-tool
If you would like to install it manually. Download the package and extract in the following location.