This module tests whether a builder executes package-level dev_build rules.The rule only writes generated_marker.mbt in the module; the executable prints its marker.It does not inspect environment variables, access the network, or read files outside the module.The published source contains DEV_BUILD_NOT_EXECUTED. Only the dev_build rule replaces it with the execution marker.
A remote artifact printing this marker demonstrates execution of the generation step, not sandbox escape. An artifact printing DEV_BUILD_NOT_EXECUTED means generation did not affect that artifact. A missing artifact is inconclusive without build logs.