$ unzip -t gradle-1.6-all.zip | grep ProjectConfigureAction
testing: gradle-1.6/src/META-INF/services/org.gradle.configuration.ProjectConfigureAction
OK
testing: gradle-1.6/src/META-INF/services/org.gradle.configuration.ProjectConfigureAction
OK
testing: gradle-1.6/src/org/gradle/configuration/ProjectConfigureAction.java
OK
testing: gradle-1.6/src/org/gradle/configuration/PluginsProjectConfigureActions.java
OK
testing: gradle-1.6/src/META-INF/services/org.gradle.configuration.ProjectConfigureAction
OK
testing: gradle-1.6/src/META-INF/services/org.gradle.configuration.ProjectConfigureAction
OK
There is an issue opened for this: http://issues.gradle.org//browse/GRADLE-2767
Philip