https://www.theverge.com/2019/4/16/18410721/apple-macos-10-14-4-update-macbook-air-new-brighter-software

Apple’s latest macOS software update may have made your 2018 MacBook Air’s display brighter. Those who eventually install the update might be pleasantly surprised to find that their laptop’s Retina display is suddenly 100 nits brighter than it was before, for a new total of 400 nits brightness.