Giffard Fleur de Sureau Sauvage--or wild elderflower liqueur--is made in a maceration of dried elderflowers harvested in the wild ("maceration" means the flowers are immersed in the spirits allowing them to soak up the aroma and essence somewhat like tea). This gives the liqueur a warm, golden-yellow color and floral flavors. They suggest drinking with ice or topped on champagne.
Giffard is a French company specializing in a wide variety of liqueurs and eua-de-vie among other products. Some of those extra products are flavored cocktail syrups (or "sirop"). They are generally sweetened with pure cane sugar.