I was working with Eagle 4.16r2 (Yes I know its old), and when I work on my project in it, I happen to save my work frequently as files with extensions .brd and .sch.
I just did a backup and now I see a ton of files which I did not create. The core name is the same name I used but the extensions are .s#n and .b#n where n is a number (and '#' is actually in the extension), and it seems each of these files that are created roughly are the same size in disk space as the ones with the proper extensions.
In the program itself when I'm browsing for the files, only the files with the proper extensions are listed.
So is it always safe to delete files with extensions containing non-alphanumeric characters?