String query for ES searches question

Keywords includes all the other fields already. Is it duplicate? and this equals to set each field ^2 times weight.  Not sure why write this way.  
```
def search_es(es_query: str) -> Dict:
'fields': [
    'subject',
    'displayId^3',
    'version',
    'name',
    'description',
    'type',
    'keywords'
]```