AndroidX uses busytown/ directory to wrap build bot invocations to a single command per build target. Each one of these scripts receives DIST_DIR, OUT_DIR, and CHANGE_INFO enviroment variables. DIST_DIR is a directory for putting build artifacts that should be saved. OUT_DIR is a directory to write temporary build outputs. CHANGE_INFO points to a file that allows build system to know what changed for a given change that is being built.
AndroidX build bots use Gradle Remote Build Cache to speed up build targets. GCP build cache Gradle plugin is used to connect to a GCP Storage bucket androidx-gradle-remote-cache from the androidx-ge project.