confusing behaviour of links

Some menu links open in a new page; some don't.
There is no indication beforehand which will happen.

This is a problem because it affects navigation back to the original page:
- do I press the back button?
- or do I close the tab?

I have seen suggestions that new tabs should almost never be used, as users should be able to choose for themselves how they wish to open links.

Review the ASF Website's menu-link implementation and identify where link-opening behavior is configured. Compare the affected links, then determine a consistent navigation behavior or clear indication for users. Done means menu links behave consistently and users can tell how navigation will work before activating a link.

Written by the indexing model from the issue text.