diff --git a/src/Pure/Admin/build_e.scala b/src/Pure/Admin/build_e.scala
--- a/src/Pure/Admin/build_e.scala
+++ b/src/Pure/Admin/build_e.scala
@@ -1,144 +1,144 @@
 /*  Title:      Pure/Admin/build_e.scala
     Author:     Makarius
 
 Build Isabelle E prover component from official downloads.
 */
 
 package isabelle
 
 
 object Build_E
 {
   /* build E prover */
 
   val default_version = "2.5"
   val default_download_url = "https://wwwlehre.dhbw-stuttgart.de/~sschulz/WORK/E_DOWNLOAD"
 
   def build_e(
     version: String = default_version,
     download_url: String = default_download_url,
     verbose: Boolean = false,
     progress: Progress = new Progress,
     target_dir: Path = Path.current)
   {
     Isabelle_System.with_tmp_dir("build")(tmp_dir =>
     {
       /* component */
 
       val component_name = "e-" + version
       val component_dir = Isabelle_System.new_directory(target_dir + Path.basic(component_name))
       progress.echo("Component " + component_dir)
 
       val platform_name =
         proper_string(Isabelle_System.getenv("ISABELLE_PLATFORM64"))
           .getOrElse(error("No 64bit platform"))
 
       val platform_dir = Isabelle_System.make_directory(component_dir + Path.basic(platform_name))
 
 
       /* download source */
 
-      val e_url = download_url + "/V_" + version + "/E.tgz"
-      val e_path = tmp_dir + Path.explode("E.tgz")
-      Isabelle_System.download(e_url, e_path, progress = progress)
+      val archive_url = download_url + "/V_" + version + "/E.tgz"
+      val archive_path = tmp_dir + Path.explode("E.tgz")
+      Isabelle_System.download(archive_url, archive_path, progress = progress)
 
-      Isabelle_System.bash("tar xzf " + e_path, cwd = tmp_dir.file).check
-      Isabelle_System.bash("tar xzf " + e_path + " && mv E src", cwd = component_dir.file).check
+      Isabelle_System.bash("tar xzf " + archive_path, cwd = tmp_dir.file).check
+      Isabelle_System.bash("tar xzf " + archive_path + " && mv E src", cwd = component_dir.file).check
 
 
       /* build */
 
       progress.echo("Building E prover ...")
 
       val build_dir = tmp_dir + Path.basic("E")
       val build_options =
       {
         val result = Isabelle_System.bash("./configure --help", cwd = build_dir.file)
         if (result.check.out.containsSlice("--enable-ho")) " --enable-ho" else ""
       }
 
       val build_script = "./configure" + build_options + " && make"
       Isabelle_System.bash(build_script,
         cwd = build_dir.file,
         progress_stdout = progress.echo_if(verbose, _),
         progress_stderr = progress.echo_if(verbose, _)).check
 
 
       /* install */
 
       File.copy(build_dir + Path.basic("COPYING"), component_dir + Path.basic("LICENSE"))
 
       val install_files = List("epclextract", "eprover", "eprover-ho")
       for (name <- install_files ::: install_files.map(_ + ".exe")) {
         val path = build_dir + Path.basic("PROVER") + Path.basic(name)
         if (path.is_file) File.copy(path, platform_dir)
       }
       Isabelle_System.bash("if [ -f eprover-ho ]; then mv eprover-ho eprover; fi",
         cwd = platform_dir.file).check
 
 
       /* settings */
 
       val etc_dir = Isabelle_System.make_directory(component_dir + Path.basic("etc"))
       File.write(etc_dir + Path.basic("settings"),
         """# -*- shell-script -*- :mode=shellscript:
 
 E_HOME="$COMPONENT/$ISABELLE_PLATFORM64"
 E_VERSION=""" + quote(version) + """
 """)
 
       /* README */
 
       File.write(component_dir + Path.basic("README"),
-        "This is E prover " + version + " from\n" + e_url + """
+        "This is E prover " + version + " from\n" + archive_url + """
 
 The distribution has been built like this:
 
     cd src && """ + build_script + """
 
 Only a few executables from PROVERS/ have been moved to the platform-specific
 Isabelle component directory: x86_64-linux etc.
 
 
     Makarius
     """ + Date.Format.date(Date.now()) + "\n")
     })
 }
 
   /* Isabelle tool wrapper */
 
   val isabelle_tool =
     Isabelle_Tool("build_e", "build prover component from source distribution",
     args =>
     {
       var target_dir = Path.current
       var version = default_version
       var download_url = default_download_url
       var verbose = false
 
       val getopts = Getopts("""
 Usage: isabelle build_e [OPTIONS]
 
   Options are:
     -D DIR       target directory (default ".")
     -U URL       E prover download URL
                  (default: """" + default_download_url + """")
     -V VERSION   E prover version (default: """ + default_version + """)
     -v           verbose
 
   Build prover component from the specified source distribution.
 """,
         "D:" -> (arg => target_dir = Path.explode(arg)),
         "U:" -> (arg => download_url = arg),
         "V:" -> (arg => version = arg),
         "v" -> (_ => verbose = true))
 
       val more_args = getopts(args)
       if (more_args.nonEmpty) getopts.usage()
 
       val progress = new Console_Progress()
 
       build_e(version = version, download_url = download_url,
         verbose = verbose, progress = progress, target_dir = target_dir)
     })
 }