In August 2019, Trump sent John Bolton to the Ukraine to stop the sale of large aerospace firm to China. The Ukrainians expect something in return for not doing it.
Here's the vid from Ukraine. Only 343 views. Must watch.
"There will be a kind of proposal that will be interesting to Ukraine as a country..."
"This issue has been developing since 2017..."
The Ukrainians are asking for a QUID PRO QUO.