What is a Jubilee Year in the Catholic Church and what events did Pope Francis miss due to his health?

Jubilee Years in the Catholic Church occur every 25 years and are significant celebrations that draw many pilgrims to Rome. These are important spiritual gatherings for Catholics worldwide. Due to his hospitalization for pneumonia, Pope Francis missed presiding at a Mass for the ordination of deacons during the current Jubilee Year. Deacons, while not priests, have the important role of reading the Gospel during Mass. This absence is particularly significant as Jubilee Years feature numerous important religious events that would typically be led by the Pope.