Maybe I simply didn't find it, yet. But: Until I commit my changes I see very detailed information on what I have changed within the different models. However: For "code" reviews it would be very useful, to have that in the History dialog, too! Currently, I only see, which models have been changed but I cannot "drill down" to the detailed changes.
I would love to see that implemented. So far a workaround for this is to:
1. Create a branch before the Commit you want to review.
2. Checkout the newly created branch in step 1.
3. Merge the changes from the Commit (revision) you want to see the detailed changes in Studio Pro.
After step 3. (without Committing) you are able to see the list of detailed changes.
this is probably a prerequisite for full pull requests, see https://forum.mendix.com/link/space/studio-pro/ideas/3282