MessagePartSupportFlags

Flags indicating the level of support for message parts on this channel.

They are designed such that setting more flags always implies that the channel has more capabilities. If no flags are set, this indicates that messages may contain a single message part whose content-type is any of the types from SupportedContentTypes, possibly with some alternatives. There is no flag indicating support for alternatives. This is because the SendMessage implementation can always accept messages containing alternatives, even if the underlying protocol does not, by deleting all alternatives except the first (most preferred) that is supported. Each of the flags so far implies the previous flag, so we could have used a simple enumeration here; however, we've defined the message-part support indicator as a flag set for future expansion. See SupportedContentTypes for some examples.

Bitfield/set of flags generated from the Telepathy specification.