Config API: updateRequestProcessorChain output has empty key in inner processor definition list

  <updateRequestProcessorChain name="add-unknown-fields-to-the-schema" default="${update.autoCreateFields:true}" processor="uuid,remove-blank,field-name-mutating,parse-boolean,parse-long,parse-double,parse-date,add-schema-fields">
    <processor class="solr.LogUpdateProcessorFactory"/>
    <processor class="solr.DistributedUpdateProcessorFactory"/>
    <processor class="solr.RunUpdateProcessorFactory"/>
  </updateRequestProcessorChain>

   "updateRequestProcessorChain":[{
        "default":"true",
        "name":"add-unknown-fields-to-the-schema",
        "processor":"uuid,remove-blank,field-name-mutating,parse-boolean,parse-long,parse-double,parse-date,add-schema-fields",
        "":[{"class":"solr.LogUpdateProcessorFactory"},
          {"class":"solr.DistributedUpdateProcessorFactory"},
          {"class":"solr.RunUpdateProcessorFactory"}]}],