"spring.servlet.multipart-org.springframework.boot.autoconfigure.web.servlet.MultipartProperties": {
    "inputs": {
        "enabled": {},
        "fileSizeThreshold": {},
        "maxFileSize": {},
        "maxRequestSize": {},
        "resolveLazily": {}
    },
    "prefix": "spring.servlet.multipart",
    "properties": {
        "enabled": true,
        "fileSizeThreshold": {},
        "maxFileSize": {},
        "maxRequestSize": {},
        "resolveLazily": false
    }
}

With thanks to @ahoehma on Gitter, maxFileSize and maxRequestSize are both DataSize properties but the values are missing from properties. It looks like there is also a problem with inputs as the output above was generated with spring.servlet.multipart.max-file-size=10MB in application.properties but the input for maxFileSize is empty.

Comment From: scottfrederick

Closing in favor of #32645