RealTracks are audio format strictly but some of the RealTracks have what are called RealCharts, which are a notated representation of the RealTracks. It won't be exact, and many of the RealCharts were transcribed after they were initially created. But you can save RealCharts when you export BIAB to MIDI (it's a checkbox in RealTracks preferences).

From there, you load it into a DAW and change any notes you want; however, if you are expecting to then play those changes using the RealTrack, that isn't going to work, because RealTracks don't respond to any MIDI changes. They are pre-recorded phrases and don't follow MIDI or notation.

The RealChart is there to help you visualize what is going on. Or you can use it as a basis for creating a MIDI track, perhaps using a high quality VSTi instrument, but the RealTrack isn't going to play those changes.

To know if a RealTrack has notation or not, first go to the RealTracks Picker. Then look under the Chart column. The "N" means it has notation. Also, "Gt" means that the guitar will display a guitar tab, or if it is a bass then the bass track will display a bass tab.

Best,
Chantelle