The Export Data Dump is a REST Service that allows partners to export bibliographic records in SCSB database into their chosen format (MARCXML or SCSB Schema XML). The use case detailing this service can be found here. Information on the parameters that are to be passed as part of the REST call are detailed in the Swagger documentation found in this link, <environment>:9093/swagger-ui.html#/data-dump-rest-controller, where, <environment> can be http://uat-recap.htcinc.com (or) http://tst-recap.htcinc.com (or) http://dev-recap.htcinc.com
Related JIRA - RECAP-39 - Getting issue details... STATUS
The above diagram (Source) depicts the optimizations carried out to improve the performance of the REST service API while handling huge volume of data.
The resultant xml is generated as a MARCXML or SCSBXML, the schema is defined here.