Aha, thank you so much @kitters, that explanation makes sense. I guess I was thinking that the "Target signal" was a part of the "select from signal" mode, but it is actually part of the selector as a whole. This makes a lot more sense.

To reiterate some more in a way I understand:

diagram.png ...

I'm trying to use the "quality transfer" feature in my selector combinator, but I don't seem to be getting any outputs. Here's my input net:

2024-12-15_11-08.png

But there's nothing on the output net:

2024-12-15_11-08_1.png

I'm really not sure what I'm missing here, I expect this to work ...