Each child restraint system (CRS) should have a clear label on the CRS itself. It is to facilitate quick reference to parents apart from using its manual that comes with the CRS.
Installation warning label is required to be fixed on each rear-facing CRS (shown at the top circle in the picture). Refer here for more information on this requirement.
Additionally, an ECE-compliant CRS should also have a clear and permanent installation diagrams/labels fixed on the CRS. These labels should have different color indicators for different orientations. For CRS which is installed using a seat belt, each belt path should be labeled with different colours according to the orientation too.
Do you know what are the colors used?