This is not a behavior or Brave, but rather one of PDFJS. I’m not entirely sure about the reason it’s always prepended, but I imagine it needs that information to provide the correct path for the PDF to be viewed. cc @rebron2000 for more information on that.
So short answer no, there’s not quite a way to do what you’re looking for. A couple suggestions:
Since Brave Beta offers full extension support, you can install a pdf reader separate from the default (pdfjs) reader that comes packaged with Brave. Using this may not result in a prepended address/location (although it depends on the extension itself though so I cant confirm this)
If you’re grabbing these links from a website, if you right-click and select
Copy Link Address from the context menu when opening one of these pdf files, the path copied to your clipboard will not include the prepended section. You can use this to paste the direct link wherever you need it.
Last, and likely most annoying, the extension (and its length) is the same every time. Depending on where you’re copying the links to, you can copy and paste the links with the prepended URL included and, once all links are copied (again, its hard to tell not know what you’re trying to accomplish so I may be off base here) simply run a find all/replace for the prepended string (in this case, “chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/”).
Hope this helps!