This page allows you to change the title shown in the plot. Using the controls you can define the font, style, size, colour and gap, from the nearest axis, of the title. You can also decide to have no title shown and insert any character from the chosen font (depends on the font, but usually these include the Å sign, press the button to see the character selection window).
The text shown in the Label: field is an accurate rendering of what is shown in the plot window. The default title can be restored by setting the text of this field to blank, or to the text Using default title (this text is used so that you can see the result of any changes you're about to make).
Superscript and subscripting are available using AST Escape sequences, for instance:
AST escape sequence result
SPLAT-VO -- A VO-enabled Spectral Analysis Tool