The S curve in Excel is used to visualize a relation of two variables: how one variable impacts another and how the value of both variables changes due to this impact. It is called an S curve because the curve is in an S shape. It is used in two types of charts: line charts and scatter charts.
https://www.myonlinetraininghub.com/excel-s-curve-charts
In Microsoft Excel, the S-curve is included in two chart types: Scatter Chart and Line Chart. Using either of these, you can create an S-curve chart that plots the change in one variable in relation to another variable.
https://www.techwalla.com/articles/how-to-make-an-s-curve-in-excel
For those of you who read my articles regularly, you will have realised I have a sense of humour. Not a particularly good one, but it does exist. When people ask me what I do for a living, I tell them I work in the modelling industry. It’s fun to watch them recoil confused as they take in my physique and my alleged job.
https://www.fm-magazine.com/news/2021/jul/build-excel-models-with-s-curves.html
Related to Excel I found two concepts. In the end, both create a line that resembles an S when plotted against time.