In this edit I completely replaced a reference by a different one. This is what the visual diff showed me (not visible in historical diff):
Actually this case is a little more subtle. T166801 will mark templates as changed if their name changes (Cite_web -> Cite_book).
It's likely here that the template hasn't changed name, but semantically it is a completely different reference. Defining the threshold for a reference template being modified vs being replaced is going to be quite hard because (1) the parameters are localised and (2) at what threshold does the reference become different (e.g. what is the difference between fixing a typo in the URL, and changing the URL to another article on the same website).
I don't really care whether the reference shows up as deleted and inserted vs. changed. But all those internal changes ("mw", "listIndex", "listKey", "contetsUsed", "refListItemId") shouldn't be shown to a user. Instead, the annotation could just show something like "This reference has been changed in some way."
I'm not actually seeing any changes displayed at that URL, nor should there be since https://gerrit.wikimedia.org/r/#/c/343134/
No. Note that this only happens while reviewing the change in VE. The historical diff looks as I would expect it.
Change 371588 had a related patch set uploaded (by Tchanders; owner: Tchanders):
[mediawiki/extensions/Cite@master] VisualDiff: Show less information about ref nodes
Change 371756 had a related patch set uploaded (by Tchanders; owner: Tchanders):
[VisualEditor/VisualEditor@master] VisualDiff: Show internal list remove-inserts
Change 371756 merged by jenkins-bot:
[VisualEditor/VisualEditor@master] VisualDiff: Show internal list remove-inserts
Change 373166 had a related patch set uploaded (by Jforrester; owner: Jforrester):
[mediawiki/extensions/VisualEditor@master] Update VE core submodule to master (94532edbf)
Not quite done yet: still waiting for https://gerrit.wikimedia.org/r/371588 to get merged.
Change 373166 merged by jenkins-bot:
[mediawiki/extensions/VisualEditor@master] Update VE core submodule to master (d7bb71b95)
Change 371588 merged by jenkins-bot:
[mediawiki/extensions/Cite@master] VisualDiff: Show less information about ref nodes