The buildpack configuration can be overridden with an environment variable matching the configuration file you wish to override minus the .yml extension and with a prefix of JBP_CONFIG. The value of the variable should be valid inline YAML. See the Liberty container, OpenJDK JRE, and Spring Auto Reconfiguration framework for examples. Also, see the sample manifest.yml file that uses configuration overrides environment variables to set Liberty features and configure version of the IBM JRE.