Open a repo.
Click history in the Workspace.
Click a commit.
Click a file in the commit
See the commit message with the link to Parents.
Click the link.
You should now see the parent commit.
Right click a file and choose Log.
You should now see the log of the file with the top most commit selected with the commit message showing the link to Parents.
Click the link.

I get a dialogue telling me there is no application set to open rev://5a....30.