Sorry if the title is bad, I don't know what to call it.
The title is (roughly) accurate. Though they are web links, what you are looking at is a representation of a directory, with each "folder" link being a "subdirectory", very much like with a traditional file explorer.
When I right-click > Save As... it only wants to save it as an HTML file.
Because that's all there is (at least at the point where you are at). The primary directory listing is an HTML file and the directory links given link to more HTML files (representing further subdirectories).
How do I download this directory without saving it as a webpage?
I am going to assume what you really want is to download one or more of the files in the subdirectories.
As indicated in the comments, you can choose the proper directory and just keep clicking till you get to the correct
.iso file link (which you can right-click > Save As... to save).
On the off-chance you really do want the whole "directory", you will want to probably use a tool such as
curl. Note that
wget will do recursive downloads (i.e. follow all the directory and file links) natively, but you will need to use a script to do anything similar with
Note that each directory is likely to be very large since they contain multiple
.iso files, etc.