Google seems to always be changing something within one of their services, and the most recent tweaks that appear to be manifesting are some design changes to the search results page on mobile devices when browsing Google.com within the browser. For the moment the changes aren't official, as the screenshots below that show the difference between the way the search results page looks now and the way it may look if Google makes these changes a complete roll out aren't popping up for everyone. However, some users have reported seeing the subtle tweaks.
If you look at the images you may notice that the category headers in both images look different. Not only are they placed lower down on the page, but the overall design looks a little more flat and, at least to us, appears to have a look that is more in line with material design. The category headers for "web," "images," "videos,' and "more" are also denoted with a blue text and line in contrast to the current layout that has those headers listed in red. The options for any country, any time, and show all results has also been separated from the main header of the search results page where the search box and the Google logo are.
One other detail that is easy to pick out is that the Google logo resides directly in the middle of the new layout, and the search box seems to blend in more with the white background, almost making it less definitive visually, while also being wider as it spans across the entire width of the screen. The drop down box that appears when you hit the more tag seems to be a bit wider too, so overall perhaps Google was trying to give the layout of the search results page some more space. The layout now almost feels a little cramped, especially after seeing these new designs. Whether or not Google will roll these changes out to everyone is unclear, but should they decide to make the changes a permanent thing users will probably notice immediately.