What is the puropose of the Citrix Start-up License?

Startup License

The startup license does not affect your license count. It is used to allow Citrix
products to communicate with the license server using a continuous open
connection. Every five minutes the license server and the products send a
heartbeat message to each other to verify that they are mutually communicating.
Note Some Citrix products can operate in a disconnected mode (not connected
to the server). These products allow a user to check out a license and operate the
product for a preconfigured period of time that is set by the administrator. In this
case, heartbeat messages are not exchanged. One example of disconnected mode
is when a user checks out a Password Manager license for a laptop, and then uses
the laptop when it is not connected to the server.