A standard convention for particle-level Monte Carlo event-variation weights

Streams of event weights in particle-level Monte Carlo generators are a convenient and immensely CPU-efficient approach to express systematic uncertainties phenomenology calculations, providing variations on the nominal prediction within single sample. But lack common standard for labelling these variation streams across different tools has proven be major limitation event-processing analysers alike. Here we propose well-defined, extensible community naming, ordering, interpretation weight that will serve as basis semantically correct parsing combination such both theoretical experimental studies.