No, it’s not a day for boxing matches. Boxing Day is the day you give your servants their gifts, in boxes.
It’s the day after Christmas Day ie 26th December. It is a bank ie public holiday.
You eat leftovers. Turkey with chips or turkey with curry or turkey in a sandwich.
You may get to see neighbours of family.
You may just be ill.
Shops may be back open and sales may have started. It was always a traditional tv news story that people had been queuing outside some big shop for five days just so they could get a fur coat for £20.
Food places may be available, though not all. Staff may be taking time off, or may just be hungover. Pubs should be open. Xmas fairs and Winter Wonderland will probably be open and looking a bit sad, so time to stock up for next year?