# NOTE: This procedure sets up the default values for all URN configuration
  #       parameters used by the package downloader client.  If the force
  #       argument is non-zero, any existing values will be overwritten and
  #       set back to their default values.
  #
  proc setupDownloadServerVars { force } {
    #
    # NOTE: The URN, relative to the base URI, where the Package Signing Key
    # NOTE: The URN, relative to the base URI, where the Package Signing Keys
    #       may be downloaded.
    #
    variable openPgpKeyUrn; # DEFAULT: pkg_key
    variable openPgpKeyUrn; # DEFAULT: pkg_keys

    if {$force || ![info exists openPgpKeyUrn]} then {
      set openPgpKeyUrn pkg_key
      set openPgpKeyUrn pkg_keys
    }

    #
    # NOTE: The URN, relative to the base URI, where a login request may
    #       be sent.
    #
    variable loginUrn; # DEFAULT: pkgd_login

    variable baseUri; # DEFAULT: https://urn.to/r

    if {$force || ![info exists baseUri]} then {
      set baseUri https://urn.to/r
    }

    #
    # NOTE: The URI where the Package Signing Key may be downloaded.  This
    # NOTE: The URI where the Package Signing Keys may be downloaded.  This
    #       should return a payload containing the OpenPGP key data.
    #
    variable openPgpKeyUri; # DEFAULT: ${baseUri}/${openPgpKeyUrn}

    if {$force || ![info exists openPgpKeyUri]} then {
      set openPgpKeyUri {${baseUri}/${openPgpKeyUrn}}
    }

  #
  # <public>
  proc useServerId { {serverId ""} } {
    variable downloadUrn
    variable loginUrn
    variable logoutUrn

    if {[string length $serverId] > 0 && \
    verifyServerId $serverId
        ![regexp -nocase -- {^[A-Z][0-9A-Z]*$} $serverId]} then {
      error "server Id must be alphanumeric and start with a letter"
    }

    if {[string length $serverId] > 0} then {
      #
      # NOTE: Set the URN variables to values that should cause the
      #       specified server Id to be used (assume the server Id
      #       itself is valid and active).
      #

  #       downloader client so that a specific version will be used.  The
  #       versionId argument must consist only of hexadecimal characters.
  #
  # <public>
  proc useVersionId { {versionId ""} } {
    variable branchName

    if {[string length $versionId] > 0 && \
    verifyVersionId $versionId
        ![regexp -nocase -- {^[0-9A-F]*$} $versionId]} then {
      error "version Id must be hexadecimal"
    }

    if {[string length $versionId] > 0} then {
      #
      # NOTE: Set the variables to values that should cause the specified
      #       version Id to be used (assume the version Id itself is valid
      #       and active).
      #

set dir $pkgd(savedDir); unset -nocomplain pkgd
    }]]

    return ""
  }

  #
  # NOTE: This procedure attempts to download the Package Signing Key from
  # NOTE: This procedure attempts to download the Package Signing Keys from
  #       the remote server and save it to a local file.  This procedure may
  #       raise script errors.  The fileName argument is the name of the file
  #       where the downloaded data should be written.  This procedure is only
  #       intended to be used from the "pkgr_setup.eagle" tool script and may
  #       go away in later versions of this package.
  #
  # <internal>

  #       must be one of the literal strings "8.4", "8.5", or "8.6" when the
  #       language is "tcl" -OR- the literal string "1.0" when the language
  #       is either "eagle" or "client".  The varName argument is the name
  #       of a scalar variable in the context of the immediate caller that
  #       will receive a boolean value indicating if the specified language
  #       is actually a reference to the package downloader client itself.
  #
  # <internal>
  proc verifyLanguageAndVersion { language version varName } {
    if {[string length $varName] > 0} then {
      upvar 1 $varName isClient
    }

    set isClient false

          }
        }
      }
    }

    return ""
  }

  #
  # NOTE: This procedure verifies that the specified value is indeed a valid
  #       server identifier.  The serverId argument is the value to verify.
  #       This procedure may raise script errors.
  #
  # <internal>
  proc verifyServerId { serverId } {
    if {[string length $serverId] > 0 && \
        ![regexp -nocase -- {^[A-Z][0-9A-Z]*$} $serverId]} then {
      error "server Id must be alphanumeric and start with a letter"
    }
  }

  #
  # NOTE: This procedure verifies that the specified value is indeed a valid
  #       version identifier.  The versionId argument is the value to verify.
  #       This procedure may raise script errors.
  #
  # <internal>
  proc verifyVersionId { versionId } {
    if {[string length $versionId] > 0 && \
        ![regexp -nocase -- {^[0-9A-F]*$} $versionId]} then {
      error "version Id must be hexadecimal"
    }
  }

  #
  # NOTE: This procedure verifies the platform specified by the caller.  The
  #       platform argument must be an empty string -OR- one of the literal
  #       strings "neutral", "win32-arm", "win32-x86", "win64-arm64",
  #       "win64-ia64", or "win64-x64".  An empty string means that the
  #       associated entity does not require a specific platform.  The