'FLmqttEstablished' defined but not used [-Werror=unused-variable]

I receive the message as stated above
In the code there is " FLmqttEstablished = false;"
How do I have to understand this?

Comments

Depending on what board and

Depending on what board and core you are using there should be a "Warnings" option in the "Hardware" menu. You can turn down the verbosity of the errors to hide that one.

Without seeing your code though I can't say why it's saying unused.