Netlify allows static index.html files to match if they exist and SPA behavior to be used if nothing matches instead of a 404 (https://www.netlify.com/docs/redirects/#history-pushstate-and-single-page-apps).
It doesn't appear serve can be used in this way currently... it appears to be full SPA w/ -s or typical match html file or 404.
I don't get it. -s or --single is for that.
You are correct. This is how -s behaves.
The wording in --help threw me off: "Serve single page apps with only one index.html"
I have index.html and other html files, not only one index.html file. index.html is used as a fallback if no other routes match. The wording led me to assume index.html was used for all routes in any case.
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I don't get it.
-sor--singleis for that.