All of these tags are replaced in the subject as in the message.
{[moodle. ???]}
{[course. ???]}
{[from. ???]}
{[admin. ???]}
{[to. ???]}
{[event. ???]}
{[usertarget. ???]}
{[moodle. ???]}
This is replaced by the site data from the site. This data you filled in in Site Administration » Home Settings » Edit Settings
In place of ??? you can put any of the columns of the course table (id = 1). The main ones being:
{[moodle.fullname]} - Replaces with full Site Name;
{[moodle.shortname]} - Replaces with short Site Name;
{[moodle.summary]} - Replaces with Site Summary;
{[moodle.link]} - extra - Replaces with Moodle access link. Already in
HTML format;
{[moodle.wwwroot]} - extra - Replaces with Moodle access
URL. It's the same as in Moodle's config.php.
Availability
{[course. ???]}
In place of ???you can place any of the columns of the course table. The main ones being:
{[course.category]} - Replaces with category ID;
{[course.fullname]} - Replaces with full course name;
{[course.shortname]} - Replaces with short course name;
{[course.summary]} - Replaces with course summary;
{[course.link]} - extra - Replaces with the course access link. Already in
HTML format;
{[course.url]} - extra - Replaces with the course access link, without the
HTML tags.
Availability
Only in events that have event→objecttable == 'course'