Hi, Is there a way to see the background that has been extracted by the Background extraction tool? This would be really helpful to view and decide if its picked up unwanted features before applying the result.
It was possible but I’ve removed the feature. It is not really helpful in fact. The best way to use the tool is to apply the bkg extraction to the whole sequence.
Thank you. I thought it would show how effectively it had covered the main object (say galaxy). Could you update the tutorial to explain that its best applied to whole sequence please. That would help a lot of other beginners like me 
Different question: Is it possible to view a histogram all the time when applying changes rather than click the Histogram transformation button every time?
It is already in the tutorial. See Siril - Manual pre-processing
No, histogram is only shown when clicking on it.
Sorry, should have been more clear. I meant in this one Siril - Tutorial for a complete processing of astronomical images with Siril and its scripts it could perhaps be made clearer about benefits of removing background before stacking (or provide an option in the scripts perhaps?)
Yes but this one is for basic automated processes.
You can write a script with background extraction for each sub but this is not scheduled for basic scripts. That would take too much time.
This is why we explain that in the manual tutorial.