Browsers without borders?
How to remove title bars and borders from windows in KDE; this gives a Chrome browser like appearance to Opera and maximises screen area for any application.
Turn off KDE title bar
Alt-F3, Advanced > No border. WIll remove the border and remove the titlebar from a KDE managed window.
Or for those mouse bound the Alt-F3 window menu is accessible via right-click on either the title-bar of the window or on the application bar entry, or by left-click on the application icon in the titlebar.
File > Menu Bar to remove the menu bar and get this effect.
I installed the Compact Menu 2 button to remove the menu bar and give this effect.