args property
Args are --build-arg values. They are what lets several images off ONE Dockerfile mean different things — the sandbox classes are three entries differing only by STAGE. Validated at the k8s choke point, with VERSION and REVISION taking precedence: those are receipts the builder derives from the tag and the commit, and a caller that could overwrite them could make an image lie about which commit it is.
Implementation
Map<String, String> args;