Broader question for this issue https://github.com/plone/Products.CMFPlone/issues/2664 I don't recall seeing 'used for' before, e.g. "<Document at /newjersey/front-page used for /newjersey/front-page>". What does this mean? Is this from a new feature of acquisition? (Plone 5.1.4)
In the early time of Zope, views were not yet implemented by templates and scripts located in the file system but by objects in the ZODB, most notably DTML Methods and Script (Python)s. The (view) "context" of those views was determined by acquisition. In a textual representation, it was indicated by the "used for" phrase: think of a view used to view the thing after "used for".
That makes sense although I don't know why this would be showing up now. These are changes I'm noticing between 5.1.0 and 5.1.4 on a test site with no addons. I would expect to only never see the "used for" implicit acquisition wrapper anymore.
I am regularly using interactive debugging (--> bin/client1 debug) and there, I often display acquisition wrappers. From that I can tell you, that they always had the "used for" information; this definitely was not introduced for 5.1.4.
I agree that it seems strange to have an acquisition wrapper display in 5.1.4 when there was none in a previous version (as Zope is on its way to replace acquisition by __parent__ chaining) -- and I have no explanation for this.
Thanks Dieter, I think I have some dependencies in this buildout that aren't violating any specific package's requirements but are causing some weird behavior. I'll try scaling it back to barebones and adding in a piece at a time.