Who is familiar with *sfile* on Ubuntu 20.04?

[mahesh]

Hi there,
I recently was copying a LibreOffice file from a USB stick to the hard drive of my laptop (OS Ubuntu 20.04), when I thought that the file folder icon on the left-hand side of my screen, where my Ubuntu icons are lined up vertically, looked weird. There was a small horizontal bar at the bottom of that file folder icon that was moving from left to right, as if some downloading was going on. I had never seen such a moving bar on the file folder icon before. I also briefly saw the word sfile pop up at the top of my screen and so I quickly ejected the USB stick, logged out of the laptop. I should add that my laptop is not connected to the internet and in fact has no wifi module so the laptop cannot accidentally connect to wifi.

I am not sure what was going on and what sfile is. A quick google search indicated that there is an sfile trojan for ransomware but that is for Windows, I believe. Then there is sfile.mobi, but that's for if you are on the internet it seems.

My questions to you knowledgeable folks here on the forum:
-is such a horizontal little bar on the file folder icon normal and when does it show up?
-how can I detect on my system logs if anything weird happened during that session?
-can I look for sfile on my system via a terminal search? What command would I need to type in?

Thanks for your suggestions!