Understanding M4 competition time series Dataset
Hello,I am still  a beginner and I am trying to understand the time series dataset: “M4 comepition dataset” .The M4 dataset consists of time series of yearly, quarterly, monthly and other (weekly, daily and hourly) data, from various domain, which are divided into training and test sets . Here is the composition of the M4 dataset: the number of TS based on their sampling frequency and type:M4_dataset784×409 63.2 KBM4 dataset is supposed to be univariate dataset, but if I see in the .csv files that are available for download:https://github.com/Mcompetitions/M4-methods/tree/master/Dataset/Train, has Multiple columns too , which should not be the case for the univariate dataset as for my understanding.I am not understanding what exactly do the rows and column mean in this dataset? I also tried going through the info file given athttps://github.com/Mcompetitions/M4-methods/blob/master/Dataset/M4-info.csvbut still could not draw any conclusion.I tried looking at other place and forums too but I could not find any explaination,Can anyone help me with understanding this dataset?