Tony wrote, "I didn't have any trouble downloading Filt.zip - must be something in your Firefox setup. ..."
I think the problem is that the LTwiki website uses http: (not secure https:) in many places.? That was a problem for the main LTwiki webpages too.? Currently, for me, the main LTwiki webpage (for information about LTspice) now uses https:, but the branches for Vlad's and Bordodynov's files still do not.? I don't use Firefox, but I guess Firefox (depending on its settings) might prevent you from downloading anything with an http: URL.? Google Chrome complains mightily, but if you are persistent and ignore all its warnings about it, you can get it to download from http: URLs.? Bit of a PITA.
Andy