Hello,
Initially I thought it was the path that is used to determine whether there are new visitors requesting a chat, but I think this is the path that is used for that: /operator/users/update
If all your operators have closed their chat windows, then it is possible that this is coming from your visitors who have not yet closed their chat windows. One way to determine that is by looking at the source IP of where those requests are coming from. If they are coming from within your organization then there is a bug in the software. If it is coming from your visitors, then you have to live with this until they close their chat windows. In this case, an enhancement would be to stop requesting for chat updates once the chat thread has been closed.
These are all [educated] guesses based on quickly looking at the code. I may have missed something.