There is a Field called "Give this section a name" under the project's Release/version (/projects/xxx/versions/<verions#>/tab/release-report-all-issues) where customer need to be able to return the content of it as part of the /rest/api/3/version/<version#> call. 

Or, make that field as valid Custom Field with ID, so developers would be able to retrieve its content. 

Project managers adding content under this field, and there is no way of retrieving them by the Rest API endpoints.