I think we have enabled s3 caching for releases between 66 and 67, where previously we had no caching at all. I don't know if that was deliberate or not. We did have local caching for releases until bug 1501113.
Bug 1532236 Comment 28 Edit History
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I think we have enabled s3 caching for releases between 66 and 67, where previously we had no caching at all. See the scopes on the [last 66 beta](https://tools.taskcluster.net/groups/Ee8NgzV7QtK37NTu4RL_0w/tasks/Jflue90IRCSa8cSSG9KCWw/details) and [deved 67.0b1](https://tools.taskcluster.net/groups/bVxP6iadSoGs1uu_IY3jZg/tasks/Kk47ICR9SquAFqTCGJKYCA/details). I don't know if that was deliberate or not. We did have local caching for releases until bug 1501113.