Sorry, it’s /manager/actions/mutate_content.dynamic.php, and it’s the script that lets you edit/create the documents. The publish/unpublish timestamps are set and edited there, and the "edited_on" timestamp is also set from that.
<td><input name="pub_date" value="<?php echo $content['pub_date']=="0" || !isset($content['pub_date']) ? "" : strftime("%d-%m-%Y %H:%M:%S", $content['pub_date']);?>" onblur="documentDirty=true;" />
The various dates (create, edit, publish, unpublish) are stored as UNIX timestamps in the database, which is exactly what the UNIX timestamp was created for 30 or so years ago. It is an integer value that reflects the number of seconds from the beginning of the "UNIX epoch" back in 1970 or something like that, and there are a number of PHP functions for working with it;
strftime() (the user comments at the bottom of this page are well worth reading) is one of these for displaying it in useful formats. It’s not good for things like people’s birthdays or calender scripts, but it is great for using as a "timestamp" the creation or other management for electronic documents, since there simply weren’t any before 1970. Its being an integer value makes for compact storage in the database, but it will be a problem in 2038 or something like that when it gets too big (too many seconds from 1970), but like the "year 2000" issues, that will have to be dealt with sometime in the next 30 years.
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