Data retention according to storage-schemas.conf

I just started learning Graphite.
Let us consider the following example storage-schemas.conf given in the documentation

[garbage_collection]
pattern = garbageCollections$
retentions = 10s:14d

The retentions line is saying that each datapoint represents 10 seconds, and we want to keep enough datapoints so that they add up to 14 days of data.

Is there a rolling window of 14 days. According to my understanding, we are storing only the latest 14 days of data and the rest of the data is deleted.

Is this understanding correct?