I went to https://acousticbrainz.org/download to download acousticbrainz-gui-0.1-win.zip but as you can see the link is an
ftp:// link which neither
Firefox 88.0.1 nor
Microsoft Edge 90.0.818.56 can open, it asks you to use a program.
Tried to get ftp links to open with winscp but that didn’t work cause it asked for login, finally managed to add it to winscp manually and get the file.
I remember that Firefox used to be able to browse in ftp’s back in the day but that seems to be a thing they removed, also chromium based edge can’t do it either so this seems like an issue. You shouldn’t need an ftp client to download files these days, and file downloads should support http.