Use of the Accessibilty Checker states that guidelines indicate links to PDF documents should have a visible reference that it is to a PDF document.

Many documents are PDF documents. The WPDR blocks (and shortcodes/widgets) contain lists of documents.

These should have a Display option Show PDF file indication (default false) which when set to true will add <small>(PDF)</small> to the link for PDF documents.

Also the Latest Documents block (and Recently Revised Documents widget) will output the title with a heading level 2 and the documents with heading level 3. If there is no list title the heading level 2 is not output. This missing header level does not follow guidelines. So in this case the doceuments should be output using heading level 2.