After upgrading to Windows 11, a few users have been noticing a small file cabinet box icon at the bottom left corner of several file thumbnails (Word, PDF, Jpeg, etc.) on their Windows PC.

An update to Google Chrome seems to have affected file icons. If you use the browser as your default PDF viewer, you may notice a change. If you notice anything amiss, try a PC restart and / or a ...

As such, it could open a PDF file as long as the %PDF-header started within the first 1024 bytes of the file. There’s, however, a change in the scheme of things now.