I found these options in MarkupGoogleMap.module but they are not in the actual README.md so can easily be missed:
* // use hover box? When true, shows a tooltip-type box when you hover the marker, populated with the markerTitleField
* // this is often more useful than the default presentation google maps uses
* 'useHoverBox' => false
*
* // when useHoverBox is true, you can specify the markup used for it. Use the following (which is the default) as your starting point:
* 'hoverBoxMarkup' => "<div data-top='-10' data-left='15' style='background: #000; color: #fff; padding: 0.25em 0.5em; border-radius: 3px;'></div>",
*
* // FUll URL to icon file to use for markers. Blank=use default Google marker icon.
* 'icon' => '',
*
* // Any extra javascript initialization code you want to occur before the map itself is drawn
* 'init' => '',
I found these options in MarkupGoogleMap.module but they are not in the actual README.md so can easily be missed: