Without the provider, views cannot find the pattern template so the preview Ajax request throws an error 500.
With the provider, the pattern is used as expected.
Configuration:
my pattern is declared in my frontend theme
it is used by a content type view mode via ui_patterns_layouts and field_layouts
the view list content of this type and display theme using this view mode
Without the provider, views cannot find the pattern template so the preview Ajax request throws an error 500. With the provider, the pattern is used as expected.
Configuration: