Software knowledge resources
That list is maintained by Matthew Feickert, with help from the community. Updates and suggestions are welcome through github pull requests.
All LHC experiments use ROOT as its basic data format and in their software for reconstruction. ROOT does include the machine learning package TMVA. The community increasingly uses non CERN standard libaries like keras, scikit-learn, XGBoost, either as standalone libraries or through interfaces with ROOT. The above HEP-ML-Resources software list shows details for both options.