Composite mode and clipping

Software GIMP
1

Searching the internet, I found the following way to create a clipping mask in GIMP:
Create a layergroup with 2 layers: the top layer is the layer you want to clip, the next layer is transparent.

RMB on the top layer=>composite mode=>clip to backdrop

Now you can draw on the transparent layer and the top layers content will show through where you draw. Nice!

But what is composite mode and what does clip to backdrop do versus the other possible options: Auto, Union, Clip to Layer and Intersection)?
I can’t find that explained in the 3.0 user manual. I’m quite new to GIMP, so I would like to understand.

2

7.2. New Layer"

This seems relevant

I may experiment with its with some examples if I get the time

Google AI seems to be on it now maybe trawled your question

I only currently know the basics that you can have a transparent background from a clipping path, handy for graphic design

3

Thank you.

You are right “composite mode” is described in the manual:

Blend mode (normal, multiply, overlay etc.) determines how the color values of the layer and its backdrop are combined
Composite mode determines how the alpha values of the layer and its backdrop are combined

It would be nice to be able to search the online manual just as if it was a PDF-document.