DJB appears to have changed the license to public domain, but at some point in the past there was a license that prohibited distribution of binaries from modified source. There's still the request that the paths not be changed to comply with the FHS.

DJB has strong opinions about the construction and distribution of software. So do quite a lot of debian people. These views are incompatible.

I think the reason is low demand largely due to the fact that gnome-desktop depends on gnome-user-share (AKA: apache).

    ruby -e 'require "rack"; include Rack; \
      Server.start :app => Directory.new(".", \
      Static.new(nil, :urls => ["/"], :root => "."))'

    python -m SimpleHTTPServer

    ruby -run -ehttpd .

    function S {
      ruby -run -ehttpd . -p${1-8080}  # default to port 8080 unless given as parameter
    }

    twistd -no web --path=.

Python is nearly always installed, and that depends on nothing but the standard library. You can stick an alias in your dotfiles (I have, it's called "serve-this") and not have to worry about having twisted¹ getting to wherever your dotfiles get put. (I distribute my dotfiles over git/github, so it's really easy to move them around. More work to get Twisted.)

¹Or Ruby… or Go…

    package main

    import (
        "flag"
        "net/http"
    )

    var serveDir = flag.String("d", ".", "Directory to serve from")

    func main() {
        flag.Parse()
        panic(http.ListenAndServe("127.0.0.1:8000", http.FileServer(
            http.Dir(*serveDir))))
    }

    #!/bin/bash
    unlink /Library/WebServer/Documents
    ln -s "$(pwd)" /Library/WebServer/Documents
    echo "http://localhost/ mounted on $(pwd)"

You could always try to package it for Debian, although I understand that's not a small amount of work.

I don't know of anything else designed for security. Hard to beat DJB in that respect. If you left out the security requirement, I would say just use the Python SimpleHTTPServer. I think it's probably secure, but definitely not explicitly designed for it.

https://packages.debian.org/search?keywords=thttpd