Example of how to overide asset-admin GraphQL

Folder.yml

# app/_graphql/types/Folder.yml

# This will be merged with vendor/silverstripe/asset-admin/_graphql/types/Folder.yml
Folder:
  fields:
    'children(filter: FileFilterInput)':
      type: '[FileInterface]'
      plugins:
        sorter:
          # If we used the array syntax (e.g. [MyFolderTypeResolver, sortChildren]), 
          # it will be merged with the pre-existing value. By using the string 
          # callabale syntax, we'll override the existing value instead
          resolver: 'MyFolderTypeResolver::sortChildren'

graphql.yml

# app/_config/graphql.yml

# This will be merged with the content of vendor/silverstripe/asset-admin/_config/graphql.yml
# The actual source src for your admin schema will be something like this
# - assetAdmin: 'silverstripe/asset-admin: _graphql'
# - myAssetAdmin: 'app/_graphql'

---
Name: my-asset-admin-graphql
After:
  - '#asset-admin-graphql'
---
SilverStripe\GraphQL\Schema\Schema:
  schemas:
    admin:
      src:
        myAssetAdmin: 'app/_graphql'