I am still recovering from the shock of seeing such an oxymoron :-)
Now, the diff view looks well and can distinguish the difference easily.
This change has been deployed to partner Bugzilla  for pre-release testing, if your testing reveals any issues please update this bug.
Checked (at semi-random):
Looks great, thanks Jeff.
Btw. it seems that syntax highlight is a new feature with BZ5, correct?
(In reply to Jan Pokorný [poki] from comment #3)
> Btw. it seems that syntax highlight is a new feature with BZ5, correct?
Yes, it is using on https://diff2html.xyz/
This change is now live. If there are any issues, do not reopen this bug.
Instead, you should create a new bug and reference this bug.