Steps to reproduce the issue

Install Testing data in Joomla 4b6
Click the feed items that link to the old feeds.joomla.org urls

Expected result

A page on the internet somewhere...

Actual result

depends on your browser - most (except chrome) try to redirect to https

Because joomla/joomla-websites#1335 (comment)

All links needed an updated are changed, the following is for history purposes.

http://feeds.joomla.org/JoomlaAnnouncements -> https://feeds.feedburner.com/JoomlaAnnouncements
http://feeds.joomla.org/JoomlaSecurityNews -> https://feeds.feedburner.com/JoomlaSecurityNews
http://feeds.joomla.org/JoomlaExtensions -> https://feeds.feedburner.com/JoomlaExtensions
http://feeds.joomla.org/JoomlaDocumentation -> https://feeds.feedburner.com/JoomlaDocumentation
http://feeds.joomla.org/JoomlaExtensionDirectoryEditorBlog -> https://feeds.feedburner.com/JoomlaExtensionDirectoryEditorBlog
http://feeds.joomla.org/JoomlaSecurityVulnerableExtensions -> https://feeds.feedburner.com/JoomlaSecurityVulnerableExtensions
http://feeds.joomla.org/JoomlaMagazine -> https://feeds.feedburner.com/JoomlaMagazine

Needs fixing in the testing data.