Question: The diff view from history is a different use case to the diff view for "show changes". It is also different from a diff generated from two page version numbers which are not necessarily of the same page. Will this patch need to distinguish these cases? If the numerical value is stored in the database, then the history version may be simple, for adjacent versions. For non-adjacent versions it will still need calculating.

To be consistent with the history view, the number should be displayed before the edit summary of the right hand edit. This may be misleading in that it appears to assign the change to the last edit.

The description of the bug is wrong. The number is the change in the number of characters, not the number of characters that have changed, fortunately this is a much simpler metric to calculate!

We will be wanting to insert something like

<span dir="ltr" class="mw-plusminus-pos" title="foo bytes after change of this size">(delta)</span>

Where foo is the number of bytes and delta is the signed change.

And add total page size, not just the change in size. I've long found it frustrating that this information is visible in the history list but not in the diffs; many of us page through diffs rather than scrolling up and down in the history list (or after doing so, rather).