core/src/main/java/io/fabric8/maven/core/util/kubernetes/KubernetesResourceUtil.java
private static Map<String, String> mergeMapsAndRemoveEmptyStrings(Map<String, String> overrideMap, Map<String, String> originalMap) {
        Map<String, String> answer = MapUtil.mergeMaps(overrideMap, originalMap);
        Set<Map.Entry<String, String>> entries = overrideMap.entrySet();
        for (Map.Entry<String, String> entry : entries) {
            String value = entry.getValue();
            if (value == null || value.isEmpty()) {
                String key = entry.getKey();
                answer.remove(key);
            }
        }
        return answer;
    }
private static Map<String, String> mergeMapsAndRemoveEmptyStrings(Map<String, String> overrideMap, Map<String, String> originalMap) {
        Map<String, String> answer = MapUtil.mergeMaps(overrideMap, originalMap);
        Set<Map.Entry<String, String>> entries = overrideMap.entrySet();
        for (Map.Entry<String, String> entry : entries) {
            String value = entry.getValue();
            if (value == null || value.isEmpty()) {
                String key = entry.getKey();
                answer.remove(key);
            }
        }
        return answer;
    }
Returns a merge of the given maps and then removes any resulting empty string values (which is the way to remove, say, a label or annotation
when overriding