When I try to click a link that should display a PDF file, in probably 9 out of 10 instances, it will default to a “save as” dialog and force download. It will not preview in the browser itself, as I would expect. Kind of a fundamental function of the browser, I would think. The same links will preview fine in Chrome or Edge.
I just searched PDF link to find some examples. The first link below works properly, as I would expect. It previews within the Brave browser.
This next link is the more common result. It will not preview and will open up a download save-as dialog box.
I am using Windows 10 and experience this exact issue on three different Win10 machines using the current build Brave browser.