This question has been asked before see for example How to access full source of old commit in BitBucket?
The Bitbucket GUI used to support this. In 5 steps you could do this in a completely non-intuitive way.
A alternative way to do it was to manipulate / construct URL's manually. Unfortunately URL schemes have changed in 5.10.1 it seems.
So there is no easy way to browse repositories at specific commit. But is there still a way do this for example in 5.10.1?