PDF with 520 MB will not upload for Assistent

I knew it will not work, but i gave it a try and uploaded
the “SPR_Handbook.pdf” which contains the Helpfile of the
Smart AI Package Robot.
As with all Plugins also, PDF’s of this size will not be uploaded.
It just runs into an Error.
Is the maximum Size for an PDF to upload somewhere documented?
Generally i would expect that a system should check the filsize before starting the upload and not start the upload and then run into an error.