Apologies for the delay in replying. Support Center defaults to HTML, so any search or link click will take you to the HTML version of a manual. Once inside an HTML manual, you can switch to PDF using the button at the top-right of the page.
If you are browsing the Tessent documentation from the Documentation tab on the Tessent support landing page, you directly open the PDF by clicking the PDF button next to the manual title.
For searching, I recommend you open the search hit in HTML by clicking on the link (shown below) and then switching to PDF once inside the HTML manual, as shown in my first image. This should open the PDF to the correct page.