#
  proc setupPackageUnknownVars {} {
    #
    # NOTE: Should the HTTP request processor attempt to force the use of
    #       HTTPS for URIs that were originally HTTP?  This setting is only
    #       applicable to native Tcl.
    #
    variable forceSecureUri; # DEFAULT: true

    if {![info exists forceSecureUri]} then {
      set forceSecureUri true
    }

    #
    # NOTE: Is this HTTP request processor allowed to use plain HTTP if/when
    #       the "tls" package is not available?  This should only be changed
    #       if the "tls" package cannot be easily installed for use with the
    #       native Tcl interpreter in use.  It should be noted here that the
    #       official package repository server reserves the right to refuse
    #       plain HTTP connections, which means that changing this setting
    #       may be totally pointless.
    #
    variable allowInsecureUri; # DEFAULT: false

    if {![info exists allowInsecureUri]} then {
      set allowInsecureUri false
    }

    #
    # NOTE: Is this HTTP request processor allowed to use plain HTTP if/when
    #       the server responds with an HTTP redirect location to an original
    #       URI that was HTTPS?  Otherwise, a script error will result.
    #
    variable allowInsecureRedirect; # DEFAULT: false

    if {![info exists allowInsecureRedirect]} then {
      set allowInsecureRedirect false
    }

    #
    # NOTE: What is the default set of API keys if none were set explicitly?
    #       This list is subject to change at any time -AND- may be empty or
    #       may contain non-working API keys, please do not rely on it.
    #

      }
    }

    #
    # NOTE: This procedure was stolen from the "getEagle.tcl" script.  It is
    #       designed to process a single HTTP request, including any HTTP
    #       3XX redirects (up to the specified limit), and return the raw
    #       HTTP response data.  It may raise any number of script errors.

    #
    # <public>
    proc getFileViaHttp { uri redirectLimit channel quiet args } {
      #
      # NOTE: This variable is used to determine if plain HTTP URIs should be
      #       converted to HTTPS, if the "tls" package is available.
      #
      variable forceSecureUri

      #
      # NOTE: This variable is used to determine if plain HTTP is allowed if
      #       the "tls" package is not available.
      #
      variable allowInsecureUri

      #
      # NOTE: This variable is used to determine if plain HTTP is allowed if
      #       an HTTP redirect response contains an HTTP URI and the original
      #       URI was HTTPS.
      #
      variable allowInsecureRedirect

      #
      # NOTE: This variable is used to keep track of the currently scheduled
      #       (i.e. pending) [after] event.
      #
      variable afterForPageProgress

      #
      # NOTE: This procedure requires the modern version of the HTTP package,
      #       which is typically included with the Tcl core distribution.
      #
      package require http 2.0

      #
      # NOTE: If the 'tls' package is available, always attempt to use HTTPS;
      #       otherwise, only attempt to use HTTP if explicitly allowed.
      #
      if {[catch {package require tls}] == 0} then {
        ::http::register https 443 [list ::tls::socket -tls1 true]

        if {$forceSecureUri} then {
          if {[string range $uri 0 6] eq "http://"} then {
            set uri [appendArgs https:// [string range $uri 7 end]]
          }
        }
      } else {
        if {$allowInsecureUri} then {
          if {[string range $uri 0 7] eq "https://"} then {
            set uri [appendArgs http:// [string range $uri 8 end]]
          }
        }
      }

      #
      # NOTE: Unless the caller forbids it, display progress messages during
      #       the download.
      #

      while {1} {
        #
        # NOTE: Issue the HTTP request now, grabbing the resulting token.
        #
        set token [eval [list ::http::geturl $uri] $args]

        #
        # NOTE: Grab the HTTP response code and data now as they are needed
        #       in almost all cases.
        #
        set code [::http::ncode $token]; set data [::http::data $token]

        #
        # NOTE: Check the HTTP response code, in order to follow any HTTP
        #       redirect responses.
        #
        switch -glob -- $code {
          100 -
          101 -
          102 {
            ::http::cleanup $token; error [appendArgs \
                "unsupported informational HTTP response status code " \
                $code ", data: " $data]
          }
          200 -
          201 -
          202 -
          203 -
          204 -
          205 -
          206 -
          207 -
          208 -
          226 {
            #
            # NOTE: Ok, the HTTP response is actual data of some kind (which
            #       may be empty).
            #
            ::http::cleanup $token; break
          }
          301 -
          302 -
          303 -
          307 -
          308 {
            #
            # NOTE: Unless the caller forbids it, display progress messages
            #       when an HTTP redirect is returned.
            #
            if {!$quiet} then {
              pageProgress $channel > 0
            }

            #
            # NOTE: We hit another HTTP redirect.  Stop if there are more
            #       than X.
            #
            incr redirectCount

            #
            # TODO: Maybe make this limit more configurable?
            #
            if {$redirectCount > $redirectLimit} then {
              #
              # NOTE: Just "give up" and raise a script error.

              #

              ::http::cleanup $token; error [appendArgs \
                  "redirection limit of " $redirectLimit " exceeded"]
            }

            #
            # NOTE: Grab the metadata associated with this HTTP response.
            #
            array set meta [::http::meta $token]

            #
            # NOTE: Is there actually a new URI (location) to use?
            #
            if {[info exist meta(Location)]} then {
              #
              # NOTE: Ok, grab it now.  Later, at the top of the loop,
              #       it will be used in the subsequent HTTP request.
              #
              set location $meta(Location); unset meta

              #
              # NOTE: For security, by default, do NOT follow an HTTP
              #       redirect if it attempts to redirect from HTTPS
              #       to HTTP.
              #
              if {!$allowInsecureRedirect && \
                  [string range $uri 0 7] eq "https://" && \
                  [string range $location 0 7] ne "https://"} then {
                #
                # NOTE: Just "give up" and raise a script error.

                #

                ::http::cleanup $token; error [appendArgs \
                    "refused insecure redirect from \"" $uri "\" to \"" \
                    $location \"]
              }

              #
              # NOTE: Replace the original URI with the new one, for
              #       use in the next HTTP request.
              #
              set uri $location

              #
              # NOTE: Cleanup the current HTTP token now beause a new
              #       one will be created for the next request.
              #
              ::http::cleanup $token
            } else {
              #
              # NOTE: Just "give up" and raise a script error.

              #
              ::http::cleanup $token; error [appendArgs \
                  "redirect from \"" $uri "\" missing location, code " \
                  $code ", data: " $data]
            }
          }
          304 -
          305 -
          306 {
            ::http::cleanup $token; error [appendArgs \
                "unsupported redirection HTTP response status code " $code \
                ", data: " $data]
          }
          4?? {
            ::http::cleanup $token; error [appendArgs \
                "client error HTTP response status code " $code ", data: " \
                $data]
          }
          5?? {
            ::http::cleanup $token; error [appendArgs \
                "server error HTTP response status code " $code ", data: " \
                $data]
          }
          default {






            ::http::cleanup $token; error [appendArgs \
                "unrecognized HTTP response status code " $code ", data: " \
                $data]
          }
        }
      }

      #
      # NOTE: If there is a currently scheduled [after] event, cancel it.
      #