Appearance of Variables
In the editors in Central, variables are surrounded by blue brackets. Sometimes variables have formats that produce auto-generated content (e.g., yyyy, which automatically displays the current year) instead of plain text. In the output, variables are rendered appropriately according to the formatting from your stylesheet.
If you click an inserted variable, you can see the relevant variable set and name in the info bar.
How Variables Might Look in the Source File
How Variables Might Look in the Output