No databaseEdition Property on Certain Oracle RDS r5b SKUs from Price List API

I recently downloaded RDS offers from the AWS Price List Bulk API

https://pricing.us-east-1.amazonaws.com/offers/v1.0/aws/AmazonRDS/current/index.json

I noticed that there were quite a few Database Instance entries in the r5b family relating to Oracle BYOL that do not have a databaseEdition set and this caused some errors in my script. My understanding was that each DB instance relating to oracle and sql server engine needed to have databaseEdition to identify which edition it applies to ie Enterprise and Standard Two.

Example SKU missing databaseEdition (normally this appears after databaseEngine in the json).

   "8P23CD8KGX9XHQMJ" : {
      "sku" : "8P23CD8KGX9XHQMJ",
      "productFamily" : "Database Instance",
      "attributes" : {
        "servicecode" : "AmazonRDS",
        "location" : "EU (Milan)",
        "locationType" : "AWS Region",
        "instanceType" : "db.r5b.xlarge.tpc2.mem2x",
        "currentGeneration" : "Yes",
        "instanceFamily" : "Memory optimized",
        "vcpu" : "4",
        "physicalProcessor" : "Intel Xeon Platinum 8000 series",
        "memory" : "64 GiB",
        "storage" : "EBS Only",
        "networkPerformance" : "Up to 10 Gigabit",
        "processorArchitecture" : "64-bit",
        "engineCode" : "19",
        "databaseEngine" : "Oracle",
        "licenseModel" : "Bring your own license",
        "deploymentOption" : "Single-AZ",
        "usagetype" : "EUS1-InstanceUsage:db.r5b.xl.tpc2.mem2x",
        "operation" : "CreateDBInstance:0019",
        "instanceTypeFamily" : "R5b",
        "normalizationSizeFactor" : "16",
        "regionCode" : "eu-south-1",
        "servicename" : "Amazon Relational Database Service"
      }
    },

I also tried to see if I could get the AWS price calculator to emit this SKU by providing the same configuration (db.r5b.xlarge.tpc2.mem2x in EU Milan) but that yielded a different SKU (KSV8FMJUSC5YB833)

Is my understanding correct that Oracle databases must have a databaseEdition? If so, what are the entries from the bulk price list API that don't have database editions? Do these apply to a different type of oracle database?