http/modify/fragment.md: mention the fragment globbing trick

http/modify/fragment.md

@@ -6,3 +6,13 @@ pound sign and string at the end of the URL. Like for example
 the pound/hash sign to the end of the URL, is only intended for local use and
 is not sent over the network. curl simply strips that data off and discards
 it.
+
+## A range trick
+
+A practical way to exploit the fact that the fragment is not sent over the
+wire, is to use that field for ranges if you want to use the exact same URL
+many times on the command line.
+
+For example, download this same exact URL twenty times:
+
+    curl "https://example.com/#[1-20]"