XML output is always like a txt output = not formatted.
It used to be the browser did some formatting automatically.
But since feeds have faded away in the past few years (a trend I personally don't like), browsers removed this auto-formatting.
Thankfully there are plugins that do that nowadays. For example, this is how I see the same URL you mentioned on Chrome:
jmp.sh/EFLoP0o (it's this plugin by the way:
chrome.google.com/webstore/detail/xv-%E2%80%94-xml-viewer/eeocglpgjdpaefaedpblffpeebgmgddk)
Firefox enforces a file download by default as I just checked. Chrome simply renders the output as plain text without any plugins.
