What is this "provides" syntax in this kotlin jetpack compose code sample?

What is the "provides" syntax in this code sample and what does it do?

LocalContentAlpha provides ContentAlpha.medium

It doesn't seem to be a standard kotlin keyword and I haven't had much luck googling for queries like "kotlin provides keyword" or "jetpack compose provides".

This shows up on the Jetpack Compose codelab, full snippet below.

@Composable
fun PhotographerCard() {
    Column {
        Text("Alfred Sisley", fontWeight = FontWeight.Bold)
        // LocalContentAlpha is defining opacity level of its children
        CompositionLocalProvider(LocalContentAlpha provides ContentAlpha.medium) {
            Text("3 minutes ago", style = MaterialTheme.typography.body2)
        }
    }
}

@Preview
@Composable
fun PhotographerCardPreview() {
    LayoutsCodelabTheme {
        PhotographerCard()
    }
}