Note: This stuff is NOT hooked up on the PBE, it has simply been taken from the files. It's not done and has some quirks / placeholder stuff. Let this serve as a tentative preview of something in the works, not an end all be all look.
Here's a look at the new match history page assets thrown together - new icons & graphics all around, space to display both team comps, and a play button to be used with the new replay system.
Couldn't get a good shot of it all together but there is also room for background images - I would assume being a washed out version of the champion you played.
These would be the tabs that fit into the left of the above images.
Credit goes to redditor Pabro for the discovery.