In Xcode based development for Apple devices, WkWebView can rendering PDF pages on iOS, however, WkWebView will not render PDF on macOS. See: https://github.com/marc-medley/WKWebView-Printing-Puzzle and http://www.openradar.me/23649229 "No Method of Printing WKWebView".
Is inability to render PDF on different platforms (e.g. macOS) a limitation of the open source WebKit? or, is it due to some layer that Apple has added onto the open source WebKit?
(In other words, does/can/should direct use of the current open source WebKit support PDF rendering across different platforms?)
Do you want *actual printing* on macOS, or do you want exporting the current page to a PDF?
Because those are two very different things, even if you are "printing" to a PDF.
For the latter, we added PDF export API over in https://bugs.webkit.org/show_bug.cgi?id=195765
(No, it has not shipped in any OS release yet)
For the former, we are tracking macOS printing in radar but I can't find a bugzilla for it.
If that's what you're after, we can use this bugzilla for it.