With the release of macOS 10.14.4, the MacBook Air (2018) was updated with a display brightness …

http://bit.ly/2VLIYHr

Joe Rossignol / MacRumors:

With the release of macOS 10.14.4, the MacBook Air (2018) was updated with a display brightness of up to 400 nits, compared to up to 300 nits previously  —  As noted on Reddit, Apple has updated its tech specs for the 2018 MacBook Air to indicate that the notebook now has a display brightness …

from http://bit.ly/2VKHBsQ