Where are all the available fields


In the HTML Templates there is the header template flatsecurity.

.scMenuTHeaderFont img, .scGridHeaderFont img , .scFormHeaderFont img , .scTabHeaderFont img , .scContainerHeaderFont img , .scFilterHeaderFont img { height:23px;}

After you select it you can bind the values from {SC_VALUE_2}, {SC_VALUE_1} and {SC_EHADER} to your actual values. This is clear.

However if we look in above code we see also some other fields:

These fields do not appear in Layout to be initialised with app values.

What I want to know is:
-which is the difference, how does system knows not to add them
-where these values are comming from? Is there a place where you can see all these global available fields? Can you define these?