Okay, I've done my home work :) TL;DR: (1) The change is fresh, let's take the time to work together at making it right before 9.4*; (2) the current state with the line 3216 in org-element.el is not okay; (3) let's try implementing what Nicolas suggests wrt to attachment=>file link resolution.
* Sorry that I rushed you into having this discussion by announcing the release with such a short notice, I should have seen this was not resolve. Now into more details. - The new feature for attachments is nice and useful. And I'm quite happy Gustav is now more acquainted with org-element.el -- we need more people with a good knowledge of that core file (thanks!) - My definition of Org core link types = the minimal set of types to which other types can be translated to. Given this definition, an attachment is not a core link type as it can resolve to file type. - org-element.el should only know about core link types. - Link type resolution should happen at exporting time: I think the design consistency is worth the potential parsing time cost. - One advantage of this approach (on top of design consistency) is that exporters won't each depend on org-attach.el to deal with file attachments, as they do right now. Now, I'm not sure who wants to try implementing Nicolas suggestion to let ox.el expand attachments into file links: since you both know the issue better than I do, I suggest one of you can try? We are not pressed by time, so whoever has the energy to finish this. Thanks! -- Bastien