If this what you are looking for https://github.com/airbytehq/airbyte/tree/master/airbyte-api/src/main/java/io/airbyte/api/client

I didn't find published at maven any dependency related to .airbyte.. I solve problem with generating classes with https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator-maven-plugin/README.md and here, open api spec of airbyte: https://petstore.swagger.io/?url=https://raw.githubusercontent.com/airbytehq/airbyte/master/airbyte-api/src/main/openapi/config.yaml#/

Thanks @Harsha Teja Kanna