What exactly is the SegmentMean in OmicsCNSegmentsProfile.csv?

Hi DepMap team,
First of all, thank you very much for your great contribution to the scientific community.
I am writing here because I have a doubt regarding the OmicsCNSegmentsProfile.csv file. I am interested in the CN profile of some cell lines, but there are some of them (e.g SNU-1411) which I could only find in this file. However, after downloading the file and going through some of your discussions I am unsure about what this SegmentMean column represents. I have seen this post in which it is said that relativeCN is reported as log2(relative CN + 1), but further down there are some comments that make me understand that relativeCN = log2(SegmentMean+1). However, according to this other post, my understanding is that relativeCN=((2 ** relative CN from the dataset) - 1), so I am not sure how to interpret this SegmentMean column values. Please let me know if am not properly understanding something here. I would very much appreciate your help regarding this topic.

Moreover, what is the type of data and pipeline that you use to get this output? Can you confirm whether you use bam files as input for the GATK Somatic Copy Number Variant Discovery Workflow?

Finally, I would like to know whether there is additional copy-number information about this cell line or any raw data I could download to perform some analysis myself. Could you point me to these files if this is the case, please?

Thank you very much in advance.
Best,
Diego.