Zero is indistingushable from uppcase O

[Vormgear]

Sugestion add a slash over or dot in the zero glyph.

[alerque]

I don't think I buy the premise that they are currently indistinguishable. In fact in side by side comparisons they are clearly different and for example placing a zero in an upper case context is clearly wrong.

SILE Sample Code

\begin[papersize=a6]{document}
\nofolios\neverindent
\font[size=20pt]
\begin{raggedright}
\begin{script}
SILE.registerCommand("sample", function (options, _)
  options.family = "Raleway"
  SILE.call("font", options, {
	  "ZER0 ZERO 0123456789"
	})
  SILE.call("break")
end)
for _, weight in ipairs({100, 200, 300, 400, 500, 600, 700, 800, 900}) do
	SILE.call("sample", { weight = weight })
end
\end{script}
\end{raggedright}
\end{document}

Adding a slashed or dotted ‘0’ as a stylistic alternate is certainly something I'd entertain and anybody willing to contribute this as a PR is encouraged to go ahead, I'll help with the details of getting in merged.

...but no I don't think the default glyph shape needs to change.

[alerque]

It occurred to me later the bigger issue is probably with the (non-default) lining numbers. While less distinct, they are still different:

The narrower shape of the zero is quite common and distinguishes it from the O in context. Out of context of course either could be anything, but the same reasoning still applies: slashed or dotted zeros are not the norm for non-monospace programmer fonts and such a glyph if added should be a stylistic alternate.