I am familiar with http status codes, but recently I saw a strange line in my chrome debugger. Instead of ordinary Status Code:200 OK I saw the following: Status Code:200 OK (from ServiceWorker).

My guess is that this just tells me that ServiceWorker is somehow responsible for accessing this document, but this is just random guess. Can anyone authoritatively (without guesses, with links to respected resources) tell me what does this mean and what are the implications?