Clear dressing with herbs for salads are generally made with water and vinegar and no oil. Different vinegars (balsamic, red wine, cider etc) can be used as well as fruit acids (citric, raspberry, orange zest etc) alongside flavourings such as finely chopped garlic, onion and chives. Because they contain no oil then no emulsion is created.
The bottle is designed to be shaken to remix the dressing just before use. Some clear dressing with herb products contain thixotropic stabilisers to retain some suspension and deliver some mouthfeel.