I am requesting that GNU Emacs supports ligatures out of the box. I know
about pretty-symbols-mode, and it is great, but it is not font
ligatures.

Take my case for example: I just found the a new (new to me) font called
Monoid (https://larsenwork.com/monoid/). It provides ligatures for
various programming symbols That I would like to use. The ligatures are
provided as actual True Type Font ligatures rather than Unicode symbols
used by pretty-symbols-mode. Thus I couldn't use them at all. I even
tried to look at the source code for the font to find the character
code, but the codes for the ligature glyphs were not correct or did not
exist.

I am asking you to provide font ligatures out of the box (emacs -Q) by
using whatever fancy system that True Type Fonts use. This has become a
feature that most text editors and word processors have by
default. Emacs has no excuse.

I would also like to help but have no idea how fonts work.
Have a great day.

In GNU Emacs 26.2 (build 1, x86_64-redhat-linux-gnu, GTK+ Version 3.24.8)
of 2019-04-30 built on buildvm-06.phx2.fedoraproject.org
Windowing system distributor 'Fedora Project', version 11.0.12004000
System Description: Fedora release 30 (Thirty)

Configured using:
'configure --build=x86_64-redhat-linux-gnu
--host=x86_64-redhat-linux-gnu --program-prefix=
--disable-dependency-tracking --prefix=/usr --exec-prefix=/usr
--bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc
--datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64
--libexecdir=/usr/libexec --localstatedir=/var
--sharedstatedir=/var/lib --mandir=/usr/share/man
--infodir=/usr/share/info --with-dbus --with-gif --with-jpeg --with-png
--with-rsvg --with-tiff --with-xft --with-xpm --with-x-toolkit=gtk3
--with-gpm=no --with-xwidgets --with-modules
build_alias=x86_64-redhat-linux-gnu host_alias=x86_64-redhat-linux-gnu
'CFLAGS=-DMAIL_USE_LOCKF -O2 -g -pipe -Wall -Werror=format-security
-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions
-fstack-protector-strong -grecord-gcc-switches
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
-specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic
-fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection'
LDFLAGS=-Wl,-z,relro
PKG_CONFIG_PATH=:/usr/lib64/pkgconfig:/usr/share/pkgconfig'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND DBUS GSETTINGS GLIB NOTIFY
ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS XWIDGETS LCMS2

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=none
  locale-coding-system: utf-8-unix

Major mode: Emacs-Lisp

Minor modes in effect:
  display-line-numbers-mode: t
  show-paren-mode: t
  electric-pair-mode: t
  display-time-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  prettify-symbols-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
/home/charles/.emacs.d/elpa/flymake-1.0.8/flymake hides /usr/share/emacs/26.2/lisp/progmodes/flymake

Features:
(shadow sort flyspell ispell mail-extr emacsbug message rmc puny dired
dired-loaddefs format-spec rfc822 mml mml-sec epa derived epg gnus-util
rmail rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils suscolors-theme display-line-numbers
warnings paren elec-pair time cus-start cus-load project-run json map
finder-inf edmacro kmacro info cl rx package easymenu epg-config
url-handlers url-parse auth-source cl-seq eieio eieio-core cl-macs
eieio-loaddefs password-cache url-vars seq byte-opt gv bytecomp
byte-compile cconv cl-loaddefs cl-lib time-date mule-util tooltip eldoc
electric uniquify ediff-hook vc-hooks lisp-float-type mwheel term/x-win
x-win term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page menu-bar rfn-eshadow isearch timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese composite charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote threads dbusbind inotify lcms2 dynamic-setting
system-font-setting font-render-setting xwidget-internal move-toolbar
gtk x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 249172 76444)
(symbols 48 28706 2)
(miscs 40 98 293)
(strings 32 80014 25169)
(string-bytes 1 1975530)
(vectors 16 25557)
(vector-slots 8 1006508 65574)
(floats 8 67 399)
(intervals 56 737 53)
(buffers 992 14))