In a merge request, how to link a version to a commit?

Context: I’d like to compare the last commit of a merge request with a specified previous commit of the same merge request.

Following the doc I can see the changes between specified versions. The problem is that in my version of Gitlab (11.2.3) there is no display of the commit corresponding to the version. Only an approximate hint about the push time is given: “4 days ago”.

gitlab

How can I know to what commit those versions correspond ?