This is the Inset2 module position, which is not using a module class suffix but has the capability to do so. The Inset module position has similar characteristics yet is placed on the left side of the Mainbody area.
Module VariationsMixxmag has a range of hilites which offer diversity for your module content. The hilites are light, medium, dark, color and promo. However, only in the side positions (left and right) can the color and promo suffixes be used.
Mixxmag's hilite positions have the ability for users to select the suffixes from a tooltips based dropdown. Click on the spanner type icon in the module header to reveal the dropdown and choose the hilite you wish to show. Also, you can also collapse the content of the module using the plus/minus symbols, all using the power of Mootools.
To apply the suffixes, login into the administrator and navigate to Extensions > Module Manager. There, select your module and locate the Module Class Suffix input field. Insert your module class suffix in this box and save.