bgp capabilities...

have at it... as if there wasn't enough already... this is borderline trivia...

https://tools.ietf.org/html/rfc5492

This specification defines an Optional Parameter and processing rules
   that allow BGP speakers to communicate capabilities in an OPEN
   message.  A pair of BGP speakers that supports this specification can
   establish the peering even when presented with unrecognized
   capabilities, so long as all capabilities required to support the
   peering are supported.

which means they're not a peer breaker...

note: route refresh appears as a capability in an open message, but it is also a message, type 5...

open, update, notification, keepalive and route refresh. in numerical order by type...