The Pixel 2's Visual Core is what does most of the work when using the camera app. It helps in processing the image captured so that the phone uses less power and saves battery. Visual Core also incorporates Zero Shutter Lag to enable the point and click workflow of the Pixel 2 camera. You can learn more about the Pixel Visual Core here.
"Today we're turning on Pixel Visual Core for Pixel 2 users—a custom designed co-processor for Pixel 2. Using computational photography and machine learning (which powers Pixel's HDR+ technology), Pixel Visual Core improves image quality in apps that take photos.", Google's Ofer Shacham explains, "This means it'll be easier to shoot and share amazing photos on Instagram, WhatsApp, and Snapchat, along with many other apps which use the Pixel 2 camera. All you need to do is take the photo and Pixel 2 will do the rest. Your photos will be bright, detailed, and clear."
Google's Pixel 2 cameras have been praised for their speed and quality, which the Pixel Visual Core played a part of. With the February update, Google is opening up Visual Core for all camera apps which target API level 26. By extending this level of quality to third-party apps, Google is letting Pixel users take advantage of full power their camera without needing to first use Google's dedicated camera app.
You need not do anything once you receive the update, it'll be applied automatically to any apps which support it. This update is rolling out with the Pixel's February security update and should reach most users over the next few weeks.
Via Google Blog