Optionalapp_The name of the application to be attributed.
Optionaldisplay_Any display text that the client should use with the attribution.
OptionallogoA specific logo that the client should use with the third-party app attribution.
The canonical URL to the source content in the third-party app.
Attributes something to a third-party app.
See
https://www.tumblr.com/docs/npf#attribution-type-app