[CentOS] somewhat OT -- are .appimage files safe?

Hello all.

I'm in the midst of trying to transfer a G+ community to something else. 
I came across this site--

https://blog.friendsplus.me/export-google-plus-feeds-45926c925891

that actually has an advanced "exporter" app but it is an ".appimage" 
app. I am not familiar with this at all and was wondering if someone on 
this list is.

Thanks for any help.

-- 
"Less is more."
----------------
MzK