[Azure Event Hub] Difference between two connections string

Hello,

I try to connect my kafka to an eventhub. I follow steps on official microsoft tutorial , Integrate Apache Kafka Connect support on AzureEvent Hubs (Preview)

But in file configuration ( connect-distributed.properties ) i don't understand a little part.

In this line sasl.jaas.config=org.apache.kafka.common.security.plain.PlainLoginModule required username="$ConnectionString" password="{YOUR.EVENTHUBS.CONNECTION.STRING}";

What is the difference between the $ConnectionString and YOUR.EVENTHUBS.CONNECTION.STRING ?

Best Regards.

Briac