> It's not a big issue, but the file names in new.txt are 
not 
> always correct, if the link has url-encoded characters (I 

I don't see the problem 

> 2020:39:54%20GMT	www.hal-
> pc.org/~clement/Simulations/Physlets/Molecular%
> 20Pius/Browian%20Motion.html	browian%20motion.html

The remote filename is:
www.hal-pc.org/~clement/Simulations/Physlets/Molecular%
20Pius/Browian%20Motion.html

and the local one is:
browian%20motion.html

If the %20 were noted as spaces, some script would have had 
problems with that (cut)

A simple s/%20/ /g should do the trick.