What is a thread with name "uikit datasource diffing"?

I am using Diffable Datasource in an app.

I stop app at breakpoint with image loading before dispatch on background thread ( network ).

I see a thread with name com.apple.uikit.datasource.diffing.
It is a serial thread with number 1 and I suppose it is main thread (stack says so).
However, could anybody describe a purpose of this thread and, especially, label name.

Maybe it is not a main thread.
What is a thread with name "uikit datasource diffing"?
 
 
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