Piping to a script block

This code works but I don’t understand why.

https://gist.github.com/macfarmw/67e318423aeb15184c623eca22b56b59

Is this dot sourcing a script block or something else?

Yeah, it’s essentially dot-sourcing a script block. Kinda. $_ represents the pipeline object being input to the script. Visually, I find it a poor practice - it isn’t appreciably different from using ForEach-Object, and it’s not as easy to understand.

Yep. Confused me.

Thanks.