In practice, resource owners do not always properly configure their origin server to provide the correct Content-Type for a given representation. Some user agents examine the content and, in certain cases, override the received type (for example, see [Sniffing]). This "MIME sniffing" risks drawing incorrect conclusions about the data, which might expose the user to additional security risks (e.g., "privilege escalation").
やる必要があるのか?ないです