Web feed plugin displaying html content instead of xml

Hello, we are using OJS with PHP 7.4.33 on Linux.
We are using a personalized theme plugin but the issue occur as well with “Health Sciences Theme”
When the web feed plugin is activated and added to the sidebar (Appearance/Setup) :

Web feed

It’s when i click on one of the proposed feed that the problem occur : instead of directly accessing to the xml content I get this :

web feed in html

And I have to go to the source to get the xml :

web feed source xml

What is bewildering is that in the web feed plugin source code it’s explicitly written that the page should open as a xml file :

Web feed mime type

But it clearly failed to do so because when I inspect it via web console I get this mime type :

web feed html inspect

So is it a bug or a feature ? Is there a quick fix ?

Safari has no problem and passes the XML stream to a corresponding RSS reader. Firefox shows the problems as you described (e.g. interprets the mime type as HTML).
Indeed the plugin forgets to set the HTTP Content-Type Header correctly.

I’ve opened a GitHub issue.