Do any of the mass storage device bootloaders allow generic file access?

I was wondering...

I know MSD bootloaders exist for the Zero, but I was wondering if they allow any file to be uploaded to the board in addition to the bootloader, and if they include helper functions to allow you to access said files?

Specifically, I thought it would be useful to be able to drop a text file onto the device that contains some configuration information the end user can easily modify.

That would be a really nice feature, I can see alot of uses and flexability being able to do that.