https://github.com/openssh/openssh-portable/commit/65909fa114e7dd7511800db2b7bacb8774afe887

  Marking interactive session data with DSCP value EF (RFC3246, RFC3247)
  helps inform the network on relative priority compared to other traffic.
  This is especially useful for differentiated treatment over wireless media.

  Following the reconciled IETF Diffserv to IEEE 802.11 mappings (RFC 8325),
  traffic marked with DSCP value EF maps to User Priority 6 in QoS Control,
  in turn mapping to the high priority WMM AC_VO access category.

https://github.com/openssh/openssh-portable/commit/289239046b2c4b0076c14394ae9703a879e78706

  Now the QoS value will change to the non-interactive IPQoS whenever
  a "non-interactive" channel is open; basically any channel that lacks
  a tty other than agent forwarding.

  This is important now that the default interactive IPQoS is EF
  (Expedited Forwarding), as many networks are configured to allow
  only relatively small amounts of traffic of this class and they will
  aggressively deprioritise the entire connection if this is exceeded.