I'm trying to grok emoji-sequences.txt

[Karl Williamson]

The first lines of that file are:

# emoji-sequences.txt
# Date: 2020-08-31, 01:06:24 GMT
# © 2020 Unicode®, Inc.
# Unicode and the Unicode Logo are registered trademarks of Unicode, 
Inc. in the U.S. and other countries.
# For terms of use, see http://www.unicode.org/terms_of_use.html
#
# Emoji Sequence Data for UTS #51
# Version: 13.1
#
# For documentation and usage, see http://www.unicode.org/reports/tr51
#
# Format:
#   code_point(s) ; type_field ; description # comments
# Fields:
#   code_point(s): one or more code points in hex format, separated by 
spaces
#   type_field, one of the following:
#       Basic_Emoji
#       Emoji_Keycap_Sequence
#       RGI_Emoji_Flag_Sequence
#       RGI_Emoji_Tag_Sequence
#       RGI_Emoji_Modifier_Sequence
#     The type_field is a convenience for parsing the emoji sequence 
files, and is not intended to be maintained as a property.
#   short name: CLDR short name of sequence; characters may be escaped 
with \x{hex}.
#
# For the purpose of regular expressions, each of the type fields 
defines the name of
# a binary property of strings. The short name of each property is the 
same as the long name.
#

My issues are

short_name is mentioned but I don't see it appearing in the file

It says that 'type_field' is not intended to be a property, but then it 
says the type fields define the name of properties of strings.  I don't 
understand