MediaWiki:Common.css
/***** Overcome mediawiki bug whereby the WikiEdit sprite is a no-show *****/
.wikiEditor-toolbar-spritedButton {
background-image: linear-gradient(transparent, transparent), url("/extensions/WikiEditor/modules/images/toolbar/button-sprite.svg?v=001") !important;
background-position: 0px 0px; /* This gets over-ridden with inline style to move sprite into view of relevant part */
background-repeat: no-repeat !important;
}