For Steam users, official bush trips are in this path and can be imported to Bush Trip Manager (BTM)
C:\Users\XXXX\AppData\Roaming\Microsoft Flight Simulator\Packages\Official\Steam
Example directory: microsoft-bushtrip-california
Not, all the directories contain the word bushtrip is in correct Bush trip format 
The folder must have this format to work with BTM.
I loaded most of the Microsoft official bush trips to BTM.
@darth0dan It might be a good idea have a search button added to the app some stage. Thanks.