As spotted by the folks at The Android Soul, you can see in the screenshot to the right that there are several websites marked with a warning sign that says “Slow to load”. These appear to be YouTube links which contains video which naturally are slower to load compared to text-based websites, which is why the IMDB link below those YouTube links has no such warning.
This will highlight to users which websites could be potentially slow to load so that they can either choose to mark it for reading later, or they could wait it out but not get frustrated as they have been warned beforehand. These changes seems to be part of Google’s effort at improving the experience of surfing on your mobile device.
Google has included other changes especially in Android M through the use of custom tabs and also deep-linking for apps so that they can launch directly from the search results page as opposed to users having to open these apps manually to try and look for the same content.