The unpkg package provider is very unstable; when using DevExtreme through libman (which is the out-of-the-box method for recent VS 2017 templates) the restore process often takes up to 10 minutes waiting for unpkg to time out, or fails because unpkg returns errors for individual files. This is apparently a known issue with unpkg, as referenced in this libman GitHub issue:
https://github.com/aspnet/LibraryManager/issues/370
"I'm finding that the libman restore command works reliably with cdnjs, but referencing the provider unpkg (which works within the IDE), consistently fails via the restore command"
Would it be possible to host DevExtreme on cdnjs, or some other libman-compatible package provider, instead of unpkg?