Enable public linked assets
As many designers will compare AdobeXD features with Sketch, and many Sketch Library use RSS feed to keep update their own librairies with users. I think it's a mandatory for BIG adoption by designers and companies to support RSS feeds like Sketch do.
Take a look :
As well as hosting your Libraries on Sketch Cloud, you can also host your Library file on any online server, publish an RSS that points to it, and have Sketch subscribe to the RSS to get updates when the Library is updated. To do that, just use a link in this form: sketch://add-library?url=URLEncodedPathToRSS
For an example of what an RSS looks like, here’s the one for our macOS Library: https://client.sketch.cloud/v1/shares/VEp78/rss
That's a reason why Apple didn't put a library for iOS 13 yet as it's in a beta test but provide it for Sketch.
Because it's easier for them to just update their library. There is no need to upload the XD file in order to get users download it and open it or save it in their cloud documents.
Kevin Vavelin commented
Well, I don't know how to explain that. I think it's library publicly available updated dynamically, like Sketch do already (see the screenshot attached).
When a publisher update his library, we have an indication that an update is available and we can update it without additional actions (like we actually do in XD, we have to download the UI Kit, then upload it to Cloud Documents)