You need to search the net for how to configure how file types are handled in your preferred browser: https://www.ecosia.org/search?tt=mzl&q=firefox+how+to+change+pdf+behaviour
@Tim Another bug relating to addons page. if you do a search for a plugin e.g. log you get two pages of add-ons. when you click on page 2 - you no longer are filtering by your search item (it just displays the unfiltered output - i.e. you can't see the second page of add-ons for a searched item.
I have followed the spinx search installation documentation but it still doesn't work. can anyone help me? I will give paypal USD 5 maybe not too big but as a reward my site forum in https://www.ndopok.org thank u