2021-09-14 In there is a discussion of the "Content-Disposition" header field and the description of the initial values allowed in this header. Additional values may be registered with the IANA following the procedures in section 9 of . Standards Track or IESG-Approved Experimental RFC inline displayed automatically (none) attachment user controlled display filename, creation-date, modification-date, read-date, size, handling form-data process as form response name, filename signal tunneled content to be processed silently handling alert the body is a custom ring tone to alert the user handling icon the body is displayed as an icon to the user handling render the body should be displayed to the user handling recipient-list-history the body contains a list of URIs that indicates the recipients of the request handling session the body describes a communications session, for example, an RFC2327 SDP body handling aib Authenticated Identity Body handling early-session the body describes an early communications session, for example, and [RFC2327] SDP body (none) recipient-list The body includes a list of URIs to which URI-list services are to be applied. (none) notification the payload of the message carrying this Content-Disposition header field value is an Instant Message Disposition Notification as requested in the corresponding Instant Message. (none) by-reference The body needs to be handled according to a reference to the body that is located in the same SIP message as the body. handling info-package The body contains information associated with an Info Package (none) recording-session The body describes either metadata about the RS or the reason for the metadata snapshot request as determined by the MIME value indicated in the Content-Type. (none) First Come First Served filename name to be used when creating file creation-date date when content was created modification-date date when content was last modified read-date date when content was last read size approximate size of content in octets name original field name in form voice type or use of audio content handling whether or not processing is required preview-type Internet media type (and parameters) of the preview output desired from a processor by the author of the MIME content reaction Permit a recipient to respond by signaling basic reactions to an author's posting, such as with a 'thumbs up' or 'smiley' graphic Not Defined Voice-Message Voice-Message-Notification Originator-Spoken-Name Recipient-Spoken-Name Spoken-Subject Not Defined required body must be understood optional body may be silently discarded