where to find blue channel script

[denzjos]

The original script is working in gimp 2.10.24 windows 10 as it is ment to be (legacy modes). For me that's alright. Thanks for the replies.
   

[Krikor]

After a new investigation, I found that the following changes are enough for the steps of the original tutorial to have the desired effect:

1- Change the Color mode to the HSL Color mode (white layer);
2- Keep the Subtract mode in Legacy (yellow layer).

If the Subtract mode is set to Default, the use of the layer group as demonstrated in my previous post will also give the correct effect.

It seems that the way Subtract mode works on the layers below is different if used in Default mode or Legacy mode.