@davemacdo, thanks for elaborating. I’m not an engineer and I can’t speak for the MN team, but my general understanding is that to display and annotate a webarchive inside MN, it would be necessary to use a code framework like WebKit, and then make all the existing MN annotation support work with that. It’s probably do-able, but it strikes me as a non-trivial task. Again, I’m not an engineer, but WebKit is a fairly complicated framework. AFAICT, there isn’t support for rendering HTML in the current version of MN. The notecards seem to use a combination of markdown and RTF internally.
If you simply want the ability to attach existing webarchives to notecards, that’s probably much more do-able. MN could copy the webarchive files to the internal folder that is used for PDF files, and maintain links to them. It would then be possible to open an attached/saved webarchive in your preferred browser. MarginNote could be used to manage the webarchives with categories, as you suggest. I think this is roughly how Bookends handles webarchives. If you haven’t already had a look, Bookends is a really excellent app. It’s primarily a reference manager, but has pretty good support for PDFs and file attachments (e.g., webarchive files), too.
Towards your original point, it would also be helpful if MarginNote provided better support for x-callback-url. This is a scheme for inter-application services on iOS, but it is used by many macOS apps as well. MarginNote can respond to requests to display existing notes via URLs, but AFAICT not to x-callback-urls. It would be good if notes could be added via an x-callback-url, or, in the case of your request, that webarchives could be added/attached to MN.
By using x-callback-urls, workflows on iOS, and services on macOS, it would be possible to create a pretty good web clipper. I have done this for the Bear notes app, which is possible because Bear has good support for x-callback-url.
So, my first request would be that MarginNote add support for x-callback-urls, as a step towards the ability to receive and add clippings (could just be text, but could be webarchives, etc.). Specifying the “destination” for these clippings inside MN is something I’m not clear about, but I imagine it would not be difficult to come up with a workable solution.
MN already responds to a URL scheme (i.e., marginnote3app://) in a limited fashion, and somebody did some work on openURL for MN, but it’s unclear to me what that really does and how to make it work. Parenthetically, the whole area of MN plugins still feels quite vague to me. Even the nomenclature is vague. Are we talking about “plugins” or “add-ons” or “extensions” or… ? Are they the same? What’s supported, exactly? When do we get completed documentation in English? Etc.
In short, all the usual unanswered questions.