PDF - Link Target
Accessible PDFs do not open in a new window, and the link target is not announced to the screen reader user.
Ensure downloadable files have been remediated to work with screen readers and open in Adobe Acrobat or reader.
Provide link text in content of the page that clearly indicates to screen reader users what the link target is (external web page, downloadable file, etc.) with alternative text, giving users control over choosing what to do with the target file (open in external app, download, etc.).
<a href="knitting.html" target="_blank">All about Knitting (opens in new window)</a>
Consider use an icon following the link text (but still within the hyperlink), and use alternative text to describe what clicking the link text will do to the user.