in src/main/java/org/apache/maven/shared/invoker/MavenCommandLineBuilder.java [209:216]
protected void setProfiles(InvocationRequest request, Commandline cli) {
List<String> profiles = request.getProfiles();
if ((profiles != null) && !profiles.isEmpty()) {
cli.createArg().setValue("-P");
cli.createArg().setValue(String.join(",", profiles));
}
}