The "Review request changed" boxes haven't been touched since they were

first introduced back in 2006 or 2007. Since then, we've added file

attachments, improved the information available on diffs, introduced

Markdown, and added extension-provided fields. All of which the old

boxes did a terrible job at representing.
This introduces a complete overhaul of the design and capabilities of

these boxes. Every bit of information is now more detailed, making it

easier for people to see exactly what has changed at a glance.
Text area fields, like Description, are now rendered as Markdown, but

presented in a unified diff format. It's easy to see what changed in the

text, and to even see small changes like a corrected word within a line.

This works much like the diff viewer, except not side-by-side.
Simpler text fields, like Branch show the before and after, one on top

of the other, helping to see what changed. These are also presented in a

diff-like view, though much smaller. By placing one above the other,

instead of one to the side of the other, it's easier to see what has

changed.
Lists share the same design as the text fields, except there's one row

per removed entry and one per added.
Diffs are greatly improved. An uploaded diff still shows the revision, a

link to the diff, and the "Show changes" link. Along with that, it now

shows the raw insert/delete count, and a partial file listing, complete

with complexity icons. If the diff hasn't been viewed yet, the

complexity icons just show the proportion of inserts/deletes, but after

it's viewed and the lines are calculated, it'll show the same

information that the diff viewer shows.
File attachments now show the thumbnails for the files that were added

or removed. These are just like the ones on the review request file

listing, but without the editing capabilities. They do have reviewing

capabilities, though, so a user can immediately begin reviewing the

added files without going to the main file listing.

Simple text fields (Branch, Summary, Commit, etc.):

Changed from blank to a value
Changed from a value to another value
Changed from a value to blank
For Commit, I changed values by posting new diffs.

List fields (Depends On, Reviewers):

Same general tests as with simple text fields
Deleted multiple items, and saw one per line.
Added multiple items, and saw one per line.
Saw the review request summaries for Depends On.

Bugs field:

Removed/added multiple entries, and saw only one add and one remove line.

  The bugs were comma-separated on a single line, which is nicer, since

  bug IDs are generally smaller.

Text area fields (Description, Testing Done):

Entered lots of Markdown, including code samples, links, and images. Saw them

  all render.
Changed all those types of content, including changes within code samples

  and changes to lines with images. The formatting didn't break, and the

  changes were properly represented.
Changed words in a line, and saw the changed regions highlighted.

Screenshot/file attachment captions:

Opened review requests with caption changes, and saw that they were displayed

  correctly, and links all went to the right places.

File attachments:

Uploaded file attachments. Saw the thumbnails. I couldn't edit them, but I could

  review them.
Tested the Review link and the new Comment link.
For the New Comment link, I created a comment and saw the draft banner. Published

  and saw it appear in the review.

Diffs:

Uploaded a diff and saw it appear with the information and a file listing.
Checked all the links, including those on the file listing.
Verified that the order was the same as in the diff viewer, and that file anchors

  were correct even when the visible order changed.
Before viewing the diff, I saw that the complexity icons just displayed insert/delete

  counts.
After viewing the diff, the icons showed replace lines, and thickness. They were still

  generally in the same proportions as the original icons, with the replace just taking

  parts away from the insert/delete regions.

Status changes:

Closed review requests as discarded.
Closed review requests as submitted.
Re-opened review requests.

Change Description field:

Saw the change description text when I entered it.

General:

Python unit tests pass.
JavaScript unit tests pass.