I was just searching for ways to export tempo maps through making a MIDI file, a MIDI file which hopefully would include the tempo changes my project has. And I found this thread.
But since I only want to export the tempo changes, Reaper tells me that MIDI exporting fails, because there is no MIDI information to export. I don't want no other data in the MIDI file than the tempo changes, so I just keep the master track selected (where the tempo changes are entered/edited), and set Reaper to export selected tracks only.
I go by File -> Export Project MIDI ... and set the export dialog as below:
By what I read above, this ought to work .. (?)
Or do I need to manually input tempo change data as LSB in a MIDI item?