Is it normal to have a hidden “.pdf” file in my “Downloads” folder?

Question

Is it normal that there is "invisible" file (because I made all files visible) ".pdf" in my "Downloads" folder?

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Everything what I have in my downloads folder is:

170 6 Sep 22:40 .

1088 5 Sep 12:09 ..

24580 6 Sep 22:41 .DS_Store

0 1 Jun 16:06 .localized

145000 11 Jul 15:52 .pdf

Thank you in advance.