Do GarageBand AIFF files become lossless M4A Files in Cubasis?

I’m trying to understand what happens to the uncompressed AIFF files I share with Cubasis from GarageBand within an iPad Pro. They become M4A files in Cubasis. So are they lossless files in Cubasis? I think they are.

After making a track in Garageband iPad Pro, I shared the track with Cubasis. I selected the uncompressed AIFF format to share. The file appeared within Cubasis with an M4A file extension, and it was 25MB, which happens to be the same size as an uncompressed AIFF file for that track. Apple says that the M4A file extension can be used for uncompressed AIFF files.