I'm curious about what function this is

[pvppk]

I see many icons on this screenshot that look like ellipses, and I'm curious about their functions.

Can someone help me answer this?

I'm extremely grateful.

[Zoltán]

Which icons?

[pvppk]

I'm sorry, I shouldn't have said "icons."
I actually mean those "clips" that looks like ellipsis

thanks!

[Zoltán]

The clip thumbnails are created from the footage which is loaded into that clip slot.
It's also possible to load a custom thumbnail there, maybe that's what was done with this composition.