Google will use Hover cards to display memory usage of active tabs and memory freed up from inactive tabs in Chrome.
Google is working on Memory Saver feature since sometime for now.
The feature launched with aim to improve Chrome performance.
Memory Saver frees up memory from inactive tabs for other tabs and applications on device. This helps Chrome to run faster. The inactive tabs becomes active when you interact with them again.
You can able to set time period to free up memory based on tab activity in Memory saver settings, beginning from 5 minutes to 1 day. By default it was set to 2 hours.
You can able to add sites manually or from the tabs active in Chrome browser.
You can also disable Chrome memory saver if found it not useful.
Visit Settings > Performance > Memory Saver and configure settings according to your liking.
Chrome grays out favicons of discarded tabs to distinguish them from active tabs.
Till now, Chrome showed memory saving for each inactive tab that could be “small savings” or “medium savings” when you interact in address bar.
Similarly, Google is working on to show memory details of open tabs in hover cards.

Remember Tab hover Cards? No matter if you enable or set them to disabled, Chrome shows memory savings in a tool tip when you hover over. You’re not losing memory saver’s reporting for tabs.

To enable this feature, you’ve to activate “show memory usage in hovercards” flag in Chrome://flags page in Canary.

This feature is being tested in Chrome 116.
There is no ETA for when all these memory saver features will be available to public in a release.
Final words: With Memory Saver enabled in Chrome, the browser shows memory used by active tabs and the memory freed up from inactive tabs in hover cards. Just hover the mouse pointer over tabs to see this new feature.