Search bar on website returns empty results

If I:

• Go to https://tails.boum.org/
• Type “browser” in the search bar
• Press enter

Then:

• I am redirected to https://tails.boum.org/ikiwiki.cgi?P=browser
• The search result it empty: nothing appears below “search”

I think that this is a regression.

Original created by @sajolida on 8245 (Redmine)