On Wed, Jan 26 2022, Lars Ingebrigtsen wrote:
> I'm unable to reproduce this on Debian/bookworm -- Emacs 27.1 and the
> current trunk seem to select the same font.
>
> Can you post the output from `C-u C-x =' on some text, and also include
> a screenshot?

Emacs from trunk gives me:
(my xfontsel cannot make use of the font name displayed here, it says
"no names match")

             position: 4 of 145 (2%), column: 3
            character: T (displayed as T) (codepoint 84, #o124, #x54)
              charset: ascii (ASCII (ISO646 IRV))
code point in charset: 0x54
               script: latin
               syntax: w 	which means: word
             category: .:Base, L:Strong L2R, a:ASCII, l:Latin, r:Roman
             to input: type "C-x 8 RET 54" or "C-x 8 RET LATIN CAPITAL LETTER T"
          buffer code: #x54
            file code: #x54 (encoded by coding system utf-8-unix)
              display: by this font (glyph code):
    ftcrhb:-Misc-Fixed-medium-normal-normal-ko-18-*-*-*-c-180-iso10646-1 (#x36)

Character code properties: customize what to show
  name: LATIN CAPITAL LETTER T
  general-category: Lu (Letter, Uppercase)
  decomposition: (84) ('T')

There are text properties here:
  face                 font-lock-comment-face
  fontified            nil

--------------------------------------------------------------------------
Emacs 28.0.91 gives me

             position: 4 of 145 (2%), column: 3
            character: T (displayed as T) (codepoint 84, #o124, #x54)
              charset: ascii (ASCII (ISO646 IRV))
code point in charset: 0x54
               script: latin
               syntax: w 	which means: word
             category: .:Base, L:Strong L2R, a:ASCII, l:Latin, r:Roman
             to input: type "C-x 8 RET 54" or "C-x 8 RET LATIN CAPITAL LETTER T"
          buffer code: #x54
            file code: #x54 (encoded by coding system utf-8-unix)
              display: by this font (glyph code):
    ftcrhb:-Misc-Fixed-normal-normal-normal-*-20-*-*-*-c-100-iso10646-1 (#x36)

Character code properties: customize what to show
  name: LATIN CAPITAL LETTER T
  general-category: Lu (Letter, Uppercase)
  decomposition: (84) ('T')

There are text properties here:
  face                 font-lock-comment-face
  fontified            nil

--------------------------------------------------------------------------
Screenshots are attached.  I do not know why the *About Emacs* buffer
with 29.0.50 uses no fancy layout at all, but only the dull layout
visible in the screenshot.  Emacs 29.0.50 uses the same font for all
other buffers.