What are these "dot" files in my Note 4?

[Android D]

I have just noticed these today. I was getting some technical support from Samsung when they told me to install the app "Smart Tutor" so tht they could remotely access my phone. Since I put in that app (and I deleted it already), i have noticed these dot files. Don't know if they are some how related, but I keep deleting them and they come back!

 

[Rukbat]

In Linux (which is the operating system Android runs on), a dot in front of a file or folder name means that it's hidden. My Files shows hidden files. An app looking for, say, a document, wouldn't look in those folders, because it wouldn't see them. It's used for folders that only the apps (or parts of the system) that use them have to know about, or to hide an album (which is a folder) in an app like Gallery.