Click the icon on the ToolBar (or) use the shortcut Cmd/Ctrl + Shift+ E
You'll get a popup, enter the new title
a)Click on Save (or) Press Enter to Save or Esc to close the popup without saving title
(closing the Popup without saving makes the title non persistent)
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b) Click on "Edit All" in the popup to manage saved titles
Select the URL from dropdown located at the bottom of the page
Edit the Title in textbox
Click on save (or) Press Enter to save the title.
Click on delete to delete the title.
If you have any suggestion for shortcut.
Please mention it in the comments and the reason why it is better.
For Firefox : https://addons.mozilla.org/en-Us/firefox/addon/rename-tab-title/