In early 2019, Google was spotted working on a nifty feature for Chrome on desktop that would let you preview a tab by hovering your cursor over it. That capability was later released through an update to Chrome's desktop version, and now it has come to its Android version as well.
The mobile page preview allows you to take a look at what a page looks like without actually opening it by long pressing a link. It shows up in the context menu right below the "Open in incognito tab" option.
When you tap on that option, a preview of the page in question pops up. This allows you to see that page in its entirety and even scroll down to see more content as well as click on other links in the preview.
Overall, the experience is like opening the entire page, although it doesn't occupy the phone's entire screen. There's no option as well to expand the preview beyond that limit, but you can tap on a button at the top bar to fully open the page. In addition, the top bar displays the site's icon, name of the page you're trying to open, and an exit button to close the preview.
As reported by 9to5Google, the latest change comes via a server-side update as part of Chrome 89 for Android. This means you won't have to do anything to turn it on.