The real case - the customer brought me 100 pdf files named "File 1", "File 1 Back", "File 2", "File 2 Back" and so on which I combined in new single pdf file in order to print "File 1" as one, "File 1 back" as other side of page and so on.
In Page Thumbnails sidebar there is no way to see any information but page number and small content. As the content was meaningless for me to set right order of pages then the only possible way to do that was by file names. Yes there is an option to mark a bunch of files in Explorer and from popup select "Combine files in Acrobat..." but in result some pages got switched and finding right place to them wasn't fun at all.
So the option to see the names of inserted files in Page Thumbnail sidebar would make workflow much simpler and offer better control over order of pages.

Thanks!