Name,Description,Reference
sip.607,"This feature-capability indicator, when included in a
        Feature-Caps header field of a REGISTER response, indicates that
        the server supports, and will process, the 607 (Unwanted) response
        code.",[RFC8197]
sip.pns,"This feature-capability indicator, when inserted in a
        Feature-Caps header field of a SIP REGISTER request or a SIP 2xx
        response to a REGISTER request, denotes that the entity
        associated with the indicator supports the SIP push mechanism
        and the type of push notification service conveyed by the
        indicator value.",[RFC8599]
sip.vapid,"This feature-capability indicator, when inserted in a
        SIP 2xx response to a SIP REGISTER request, denotes that the
        entity associated with the indicator supports the Voluntary
        Application Server Identification (VAPID) mechanism when the
        entity requests that a push notification be sent to a SIP UA.
        The indicator value is a public key identifying the entity,
        which can be used by a SIP UA to restrict subscriptions to that
        entity.",[RFC8599]
sip.pnsreg,"This feature-capability indicator, when inserted in a
        SIP 2xx response to a SIP REGISTER request, denotes that the
        entity associated with the indicator expects to receive
        binding-refresh REGISTER requests for the binding from the SIP
        UA associated with the binding before the binding expires, even
        if the entity does not request that a push notification be sent
        to the SIP UA in order to trigger the binding-refresh REGISTER
        requests. The indicator value conveys the minimum time
        (given in seconds) prior to the binding expiration when the UA
        MUST send the REGISTER request.",[RFC8599]
sip.pnspurr,"This feature-capability indicator, when inserted in a
        SIP 2xx response to a SIP REGISTER request, conveys that
        the entity associated with the indicator will store information
        that can be used to associate a mid-dialog SIP request with the
        binding information in the REGISTER request. The indicator
        value is an identifier that can be used as a key to retrieve the
        binding information.",[RFC8599]
sip.608,"This feature-capability indicator, when included in a
		Feature-Caps header field of an INVITE request, indicates that the
		entity associated with the indicator will be responsible for
		indicating to the caller any information contained in the 608 SIP
		response code, specifically, the value referenced by the Call-Info
		header.",[RFC8688]