With Efficiency Mode, Firefox reduces power consumption and improves performance. If you want to disable Efficiency mode permanently, you have the option to do so
Google has hidden easter eggs on Search for Dog and Cat. It gives Paw prints on the screen w/ barking & meowing & purring sounds when you tap or click the paw icon
Firefox may not allow certain extensions to run on specific websites due to a new security feature called Quarantined Domains, here is how to disable it.
Microsoft is working on adding a Photo Viewer, “Edge Photo” to Edge. The feature in its current form is pretty limited, it allows viewing photos from a folder on your hard drive.
Opera One has a new tab organizing feature that automatically arranges related tabs into groups or tab islands, if you don’t like that you can disable it.