The automatic theme setting now reads the COLORFGBG environment variable (set by many terminals) to detect whether the terminal uses a light or dark background, rather than querying macOS system settings. The label changed from "Auto (follow system)" to "Auto (match terminal)" to reflect this behavior.
Evidence
Theme detection (search for "Auto (match terminal)", "COLORFGBG")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
