Re: dmy tag 
The  tag is used to inform Wikipedia bot programs which date format is in use (day-month-year in this case). The tag should not be visible to regular viewers and does not directly affect article content. Some bots may do date updating and maintenance on dates such as removing links or other date formatting, therefore a  tag ensures the bot will apply the correct date format. The other format, month-day-year, tends to be associated with American non-military articles, therefore an  tag would help the bots for that case. Hope this info helps.