http://www.berklix.com/~jhs/src/bsd/fixes/FreeBSD/src/gen/etc/services.concert.REL=CURRENT.diff
By { 12.0-ALPHA8 & 12.1-RELEASE & 2018-11-06 13.0-CURRENT } 
etc/services had moved to usr.sbin/services_mkdb/services

Not needed for 6.4

by ( 12.1-RELEASE & 13.0-CURRENT ) etc/services moved to usr.sbin/services_mkdb/services

*** 2020-03-15-13.0-CURRENT-orig/src/usr.sbin/services_mkdb/services	Sun Mar 15 21:54:11 2020
--- 2020-03-15-13.0-CURRENT-new/src/usr.sbin/services_mkdb/services	Sun Mar 15 21:56:00 2020
***************
*** 1394,1399 ****
--- 1394,1401 ----
  multiling-http	777/udp    #Multiling HTTP
  wpgs		780/tcp
  wpgs		780/udp
+ concert		786/tcp
+ concert		786/udp
  mdbs-daemon	800/tcp    mdbs_daemon
  mdbs-daemon	800/udp    mdbs_daemon
  device		801/tcp