Date and time format question

[Paul Dupuis]

I have an export routine I am writing and it expects timestamps in the 
following format:

2018-03-27T17:46:39Z

I can output LC dates and times in any format, but I personally have not 
seen this format before. The "T" is obviously just a delimited between 
the data and time, but my question is the "Z" at the end? Is this just a 
delimiter or does it indicate time zone (and in "zulu" time, i.e GMT)? 
Or something else?

Anyone seen this timestamp format before and know the details of it?

Thanks in advance,