REPLACING MIDI FILES IN SONGS

I have the songs in the Project Folder and need to change the Midi file.
But I cannot find the Folder where the Original MIDI file is held.
Where does BB Manager by default, hold its MIDI files in a song that I have in a Project.

For example: I have installed the HAND PERCUSSION BEATS folder in the song section of my Project.
When I highlight the file to change in the Main Drum Loop it displays the .bbt file, but I cannot find where the file is stored. I can change the midi file from my Workspace Location folder, but I cannot find the HAND PERCUSSION BEATS midi file folder.
Need explanation of the BB manager Hierarchy Folder options

The source midi files do not get loaded as part of a B.B. song. They are embedded in the .sng. The BBT file will export as a midi file, if you right click, (or ctrl click on a Mac) and select the option to export the midi file.

Think of it this way - when you loaded the hand percussion beats, you loaded a pbf. There was no separate folder of midi files that you added. They can be extracted, but they are not, by default, already loaded.

Thanks Phil
All good