Switch your default browser if you are Currently on battery.
Some browsers aren't as efficient as others when it comes to energy usage. By switching your browser while not plugged in, your battery will last longer before you have to find the nearest outlet.
You'll get those precious extra minutes in the airport or in that long meeting.
Current is treated as a browser. When you first launch it, you set it to be the default browser. The next time you are on battery and open a link from another app like Mail.app, Slack, Terminal it will open in the more engery efficient browser of your choice.
When this feature is on, Current will try to be more intelligent about which browser to switch to. The reasoning for this is if you are plugged in while using Chrome and then unplug, you might not be ready to switch to Safari.
It will open links in Chrome until you quit Safari or vice versa. Also in those situations where you are using both browsers, it will just use the last browser you used.
Here's a more succinct breakdown: