The theme settings dialog , accessible via Edit Theme settings (Ctrl+I), controls the two XML-Objects Theme and ThemeInfo. These define information about the skin and its author as well as its behaviour.
The name of the skin
AuthorThe author's name
E-MailThe author's E-Mail address
WebpageThe author's webpage
This defines at what distance between the edges of the skin and of the screen the skin attaches to the screen edges.
If the user enabled skin opacity in VLC's settings, the skin will have the given opacity. From 1 being nearly invisible to 255 being totally visible.
Opacity when moving
Same as above, only that this takes only effect, when the user moves a window of the skin