Inconsistent capitalisation of downloaded files

[mpatas]

In JabRef 5.0, if a pdf file is downloaded using "Download from URL" button in entry editor ("General" tab), it gets the extension "PDF" with upper case letters (that is, let's say, "Bibtexkey.PDF"). But if, after that, one changes Bibtexkey (or, presumably, something else that goes into the default file name), and chooses "Rename file to default pattern", the file gets an extension "pdf" with lower case letters (that is, let's say, "Bibtexkey1.pdf").

That seems to be inconsistent. In both cases the capitalisation should be the same (I would prefer lower case ("Bibtexkey.pdf"), but, perhaps, it is a good idea to set that in the preferences).