Do mathdesign sans serif and monospaced fonts "fake" small caps?

Question

The manual for mathdesign explains how to ensure "true" small caps are used for the main type family selected as an option, but it says nothing about whether the small caps used in other fonts are "faked".

For example

\usepackage[bitstream-charter,expert]{mathdesign}
\renewcommand{\sfdefault}{phv}

will use true small caps for Charter only if additional fonts are purchased and installed, but it is unclear if the sans serif font specified in the second line (Adobe Helvetica) will use true small caps.

Do the fonts available to mathdesign for sans serif¹ and monospaced² type support true small caps?

---

¹ Computer Modern Sans Serif, Bera sans, Adobe Helvetica
² Bera mono, Computer Modern Typewriter, Adobe Courier

Answer 1

The relevant entry in the file t1phv.fd says

\DeclareFontShape{T1}{phv}{m}{sc}{
   <-> \Hv@@scale phvrc8t
}{}

meaning that phvrc8t.tfm and, if existent, phvrc8t.vf will be used for sans serif small caps. The file phvrc8t.vf exists and its translation into human readable form with vftovp says

(VTITLE )
(FAMILY UNSPECIFIED)
(FACE F MRR)
(CODINGSCHEME EXTENDED TEX FONT ENCODING - LATIN)
(DESIGNSIZE R 10.0)
(COMMENT DESIGNSIZE IS IN POINTS)
(COMMENT OTHER SIZES ARE MULTIPLES OF DESIGNSIZE)
(CHECKSUM O 4303237440)
(FONTDIMEN
   (SLANT R 0.0)
   (SPACE R 0.27799)
   (STRETCH R 0.165991)
   (SHRINK R 0.065991)
   (XHEIGHT R 0.522998)
   (QUAD R 1.0)
   (EXTRASPACE R 0.065991)
   (PARAMETER D 8 R 0.717993)
   (PARAMETER D 9 R 0.717993)
   (PARAMETER D 10 R 0.930994)
   (PARAMETER D 11 R 0.2199955)
   (PARAMETER D 12 R 0.930994)
   (PARAMETER D 13 R 0.225)
   (PARAMETER D 14 R 0.555994)
   (PARAMETER D 15 R 0.0)
   (PARAMETER D 16 R 1.2)
   )
(MAPFONT D 0
   (FONTNAME phvr8r)
   (FONTCHECKSUM O 13550061316)
   (FONTAT R 0.8)
   (FONTDSIZE R 10.0)
   )
(MAPFONT D 1
   (FONTNAME phvr8r)
   (FONTCHECKSUM O 13550061316)
   (FONTAT R 1.0)
   (FONTDSIZE R 10.0)
   )

<...lines omitted...>

(CHARACTER C A
   (CHARWD R 0.716992)
   (CHARHT R 0.720496)
   (MAP
      (MOVERIGHT R 0.025)
      (SELECTFONT D 1)
      (SETCHAR C A)
      (MOVERIGHT R 0.025)
      )
   )

<...lines omitted...>

(CHARACTER C a
   (CHARWD R 0.582996)
   (CHARHT R 0.581494)
   (MAP
      (MOVERIGHT R 0.025)
      (SETCHAR C A)
      (MOVERIGHT R 0.025)
      )
   )

<...lines omitted...>

meaning that the character "a" is obtained as a scaled version of the upper case "A". Notice the difference: for the "A" the selected font is number 1, that is, phvr8r at design size, for the "a" the selected font is number 0 (the default), that is, phvr8r at 0.8 the design size.

So the answer is: Helvetica uses faked small caps.

Typewriter type small caps are something that I don't even consider.