enhance security by blocking Wolfram's tracker

rust/wolfree_sed_in_place/src/main.rs

@@ -63,6 +63,10 @@ fn main() -> Result<(), Box<dyn error::Error>> {
         "'www.wolframalpha.com'"
     )?;
 
+    // block Wolfram trackers
+    // https://wal.wolfram.com/js/3.0.0/wal.js
+    sed("./docusaurus/static/input/", "wal.wolfram.com", "data:,//")?;
+
     Ok(())
 }