Notifications Menu RSS Feed are not displayed detailed anymore and on Firefox the RSS Feed from Notifications Macro displays only HTML code

Steps to reproduce

1. Have an RSS extension installed in the browser (if not exists natively)
2. Have an user with notifications events in the Notifications list
3. Go to a page
4. Insert Notifications Macro (by ticking 'Use preferences of the user')
5. Click on "RSS Feed" link on the Notifications macro
6. Observe the feed displayed
7. Click on "RSS Feed" link from the user's Notifications Menu (on the Notifications Bell)
8. Observe the feed displayed

Expected results

Clicking on "RSS Feed" link from both the Notifications Macro and Notifications Menu, displays the notifications events in an RSS feed properly with details (like date/time when the event occurred, the user who performed the action).

Actual results

On all browsers (Firefox 152, Chrome 149 and Edge 149), when clicking on "RSS Feed" link from Notifications Menu, the list of events is displayed without any detail:

which could not be reproduced before, see the screenshot from XWiki 13.7 for ex.

Only on Firefox 152: When clicking on "RSS Feed" link on the Notifications macro, only some HTML code is displayed, the RSS feed is not rendered anymore:

This cannot be reproduced on Chrome and Edge on XWiki 18.4.1:

The issue could be reproduced on XWiki 17.10.9 as well, but it looks like it's an older regression (on XWiki 16.10.10 the RSS from Notifications Menu was displayed with details and on XWiki 13.7 both RSS feeds were displaying properly with details as expected).