form-data only shows up as [object Object] in Chrome/Firefox devtools

When marking a ‘multipart/form-data’ request the send data only shows up as object to an API Chrome and Firefox DevTools only show it as

Content-Disposition: form-data; name="testData"

[object Object]

(according boundary style for Firefox)

Now I am wondering if it’s the correct behaviour, or if it should show the actual data instead of only ‘object or if I can’t just simply set the ‘data’ field to my FormData object but instead of to call something like JSON.strinfify or whatnot.

Can someone clarify how this multipart/form-data should be shown if everything is working the right way?