How to make .desktop file to open with its own icon in sidebar

I have created a .desktkop file to open GitHub using brave browser

#!/usr/bin/env xdg-open
[Desktop Entry]
Name=GitHub
GenericName=GitHub
Comment=Github desktop app
Exec=/opt/brave.com/brave/brave-browser --profile-directory="Default" --app=https://github.com/
Icon=/home/parag/.icons/github-desktop.svg
Terminal=false
Type=Application
StartupNotify=true
MimeType=text/plain;
Categories=Network;Application;
Keywords=Github;gitapp;
X-Ubuntu-Gettext-Domain=Github

But the problem is that it comes as an instance of the browser with the browser icon in the sidebar.

I want it to show its own icon in the sidebar instead of the browser icon.

Is there any way to do it??

thanks in advance :))

Edit 1

I tryed Alt+F2 and typed lg and go to the windows section and here is the output

here WhatsApp opens as desired (with its own icon in the sidebar) but Github doesn't.

The only difference here is that app field for WhatsApp shows the desktop filename while for Github it shows the browser's desktop file name.

So does this mean that a desktop file opening a website will have its separate icon if only if the website is a web app?

This method is applicable on creating only 1 .desktop file

I changed my Github.desktop file and added

StartupWMClass=Brave-browser

if you are using chrome then add Google-chrome instead

Next copy the default .desktop file for the browser to ~/.local/applications

cp /usr/share/applications/brave-browser.desktop ~/.local/share/applications/brave-browser.desktop

then open the copied .desktop file

gedit ~/.local/share/applications/brave-browser.desktop

and add this below the name field

StartupWMClass=brave-browser

in the case of chrome add google-chrome instead

At the end restart your gnome-session using Alt+F2 and typing 'r' followed by Enter

Result

A separate icon for github