There's a stale version of this file on my system that reflects when Debian was installed but it brings a question to mind.
Does this file simply cause messages to appear on an event calendar or can it be used along with crontab in some way to either cause or prevent cron jobs from running if a date matches one of the dates in the file? I use cron and at jobs all the time and have thought that it would be nice to skip some jobs if the day is a holiday and the result might be not what one wanted. Right now, I don't think this file is doing a thing as it is for 2017 but this is why I am asking. I also saw versions of that file for other countries such as the UK. Thanks for all good responses. Martin McCormick