What is the use of indexDb if sw-toolbox is validating freshness of cache via date header

[minaseem]

sw-toolbox/lib/helpers.js

Line 182 in 2fb9a52

var dateHeader = response.headers.get('date');

I am a bit confused here. Why is sw-toolbox maintaining an indexDb if it is validating the freshness of cache via date header.

I know this is not an issue, but I don't know if there is any other medium to ask this question.