Unlike popular belief, there is not always a person (‘marshaller’) to guide the aircraft while parking on a stand. At many airports, pilots (carefully) manoeuvre their plane to the right spot. To assist them, so-called stop-lines are painted on the ground. Unfortunately, there are sometimes so many that things may become confusing. Furthermore, they are only on one side (no cross-check + guidance needed from Captain if First Officer is taxiing) and sometimes hardly readable (especially at night with a wet or contaminated apron).
In the image above, you see two stop-lines. The aircraft types are displayed in the small yellow markings just below the line – as you can see (even in bright sunlight) hardly readable from the flight deck.