@casiegel , as I understand from Euro Commission site , the stipend is really to defray the cost of living in the country. Thus for a US citizen/ Green Card holder, this income would be looked upon as a stipend paid to you and is income that is taxable. However, because you are having a foreign tax home ( if you are staying abroad for more than 330 days total in a continuous 12 month test period, then this income would be eligible for foreign earned income exclusion. From Euro-Union site it appears the session starts in October and so you will have to be abroad till atleast Oct of 2023 to be able to file a 12 month test period to establish foreign tax home.
Does this help ? If you need more , then please provide your immigration status ( US citizen/ Green Card or ? ), how long is your trainee period expected to be , which country ( Belgium or ? ) etc.
pk
