src/Pure/Thy/present.ML

             val base = Path.base path;
             val base_html = html_ext base;
             val _ = add_file (Path.append html_prefix base_html,
               HTML.ml_file (Url.File base) (File.read path));
             in (Url.File base_html, Url.File raw_path, loadit) end
-      | NONE => error ("Browser info: expected to find ML file" ^ quote (Path.implode raw_path)));
+      | NONE => error ("Browser info: expected to find ML file " ^ quote (Path.implode raw_path)));
 
     val files_html = map prep_file files;
 
     fun prep_html_source (tex_source, html_source, html) =
       let