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kotlinlang

Can someone explain the purpose of Semantics composable? and when to use it

I haven’t used it directly myself, but it looks like it’s used for accessibility information and identifying things in UI tests.

That's correct.  If you've got any specific questions about it I'm happy to help.  We're also currently working on some API changes here to make it a bit less confusing, among which is that we're currently planning to make it a Modifier.