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

*** 7.1-RELEASE/src/etc/services	Tue Nov 25 03:59:29 2008
--- new/src/etc/services	Sat Feb 28 23:17:44 2009
***************
*** 1,6 ****
--- 1,13 ----
  #
  # Network services, Internet style
  #
+ #     "Building Internet Firewalls" by Chapman & Zwicky 1st Ed. 9.1995 Pub:O'Reilly
+ #     Page 497:
+ #             Below 256 reserved for well known eg ftp & telnet.
+ #             From 256 to 1024 for Unix Specific EG rlogin.
+ #     I jhs am suprised it's not 256-1023 inclusive, excluding 1024.
+ #     RFC 1700 October 1994 only lists up to 255.
+ #
  # Note that it is presently the policy of IANA to assign a single well-known
  # port number for both TCP and UDP; hence, most entries here have two entries
  # even if the protocol doesn't support UDP operations.