Any example ? or an idiom name I can google ?

Groovy also does it. I have no idea what the name is though: https://mrhaki.blogspot.com/2009/11/groovy-goodness-passing-...

Not sure about the exact name. But kotlin also has "function with receiver" that together with this makes it very easy to write almost a custom domain language on top of kotlin.

Can't edit, but here's an explanation https://kotlinlang.org/docs/reference/type-safe-builders.htm...

Swift calls it trailing closure syntax

Ok so it's an explicit parameter, the function is just ~curried so you can just write it nicely.