private static boolean isModifiable(QueryProfile profile) {
        if (profile.isFrozen()) return false;
        if ( ! profile.isExplicit()) return true; // Implicitly defined from this - ok to modify then
        if (! (profile instanceof BackedOverridableQueryProfile)) return false;
        return true;
    }
Returns whether the given profile may be modified from this profile
container-search/src/main/java/com/yahoo/search/query/profile/QueryProfile.java