Anno Lucis (abbreviated A.L.) is a special way of counting years that is used by some organizations that follow the beliefs and teachings of Freemasonry.
You know how you have a birthday every year and you get one year older? Well, for Freemasons, they use a different way of counting years. They start counting from the year they believe God created the world. They call this year "Anno Mundi" (A.M.), which means "year of the world."
Anno Lucis is a special type of counting that starts from the year A.M. plus 4,000 years. This is because Freemasons believe that it took God 4,000 years to create the world before humans were created. So, when they say that it is "Anno Lucis 6019," they mean that it has been 6,019 years since they believe God created the world.
So think of it like this: Anno Lucis is a special way of counting years that is used by some people who belong to a group called Freemasons. They start counting from the year they believe God created the world, and they add 4,000 years to it to get the year in Anno Lucis. It's just a different way of measuring time!