Changes to Get a revision history for a genome assembly by genome assembly accession

added the optional property assembly_revisions/items/identical to the response with the 200 status

the assembly_level response's property default value chromosome was added for the status 200

the assembly_level response's property default value chromosome was removed for the status 200

removed the media type application/json for the response with the status default

added the media type text/plain for the response with the status default

added the optional property assembly_revisions/items/release_date to the response with the 200 status