Some more info below
https://medium.com/@rabby_io/rabby-release-announcement-564406988e2b
Seconded. Apparently, Rabby wallet has proven to be the best Web3 wallet. It is even better than Metamask in that it has one of the best UI and UX (if not the best in the industry). It was created by the guys at Debank DeFi and it is easily becoming one of the most used wallets as well. The feature you mentioned is their simulation feature. It shows a possible results from signing of a transaction so that the user so they can make an informed decision whether or not they want to go ahead with it.
It's really good stuff and I enjoy using since it has one of the best wallet security out of the box.