Hi! I was trying to implement the Kaithi script in Emacs. Everything seems
to be working fine except for two characters: Kaithi Number Sign (\u110BD)
and Kaithi Number Sign Above (\u110CD), they do not appear when inserted in
a buffer, instead it is just whitespace.
According to the Unicode standard, they behave like the Arabic Number Sign
(\u0600) which spans numbers. I have attached a render from hb-view

This is what I have written in lisp/language/indian.el
Please tell me what I am doing wrong.

;; Kaithi composition rules
(let ((consonant "[\x1108D-\x110AF]")
      (non-consonant "[^\x1108D-\x110AF\x110B9]")
      (vowel "[\x110B0-\x110B8\x110C2]")
      (anusvara-candrabindu "[\x11080\x11081]")
      (virama "\x110B9")
      (number-sign "\x110BD")
      (number-sign-above "\x110CD")
      (numerals "\x966-\x96F"))
  (set-char-table-range composition-function-table
                        '(#x110B0 . #x110B8)
                        (list (vector
                               (concat consonant vowel anusvara-candrabindu
"?")
                               1 'font-shape-gstring)))
  (set-char-table-range composition-function-table
                        '(#x110B9 . #x110B9)
                        (list (vector
                               (concat consonant "\\(?:" virama consonant
"\\)+"
                                       vowel "*\\|" consonant virama)
                               1 'font-shape-gstring)))
  (set-char-table-range composition-function-table
                        '(#x110BD . #x110BD)
                        (list (vector
                               (concat number-sign numerals)
                               1 'font-shape-gstring)))
  (set-char-table-range composition-function-table
                        '(#x110CD . #x110CD)
                        (list (vector
                               (concat number-sign-above numerals)
                               1 'font-shape-gstring))))

In lisp/internation/fontset.el
(kaithi ,(font-spec :registry "iso10646-1" :otf '(kthi nil (rphf))))