I found those hidden files/ folder on Debian/GNU Linux
 

They are .sourceslist.wso and .sourceslist.swp. in my /home/user folder
Note the dot in front of the names.
And also that .swp folder in /home
The owner is root on all of them.

-I want to know what are these for, can I delete them ?
-Are they related to the Debian popularity contest which I subscribe for ?

I am becoming less and less green every day. -- Linux is just amazing.
What impresses me the most is that it is real multi-tasking.

Thanks,

the .swp file is put there by vim when you edit a file, it is removed when vim is exited gracefully.

Are you sure the .wso file isn't .swo. If so, then if you edit a file with a stale .swp, vim will tell you that it has found a stale .swp and if you ignore it it will create a .swo file. The .swo file is used for the same purpose as the .swp. Using a different file means the original is preserved allowing you to deal with it at a later stage.

You are right I did a typo it is .swo
I don't recall using vim but I did use vi.
I will delete those 3 files.

Thanks for your answer.