A tracking bug for a few things that will need updating for future releases of Safari and Safari for iOS. This might be guesses based on what's currently in Safari Technology Preview, or recent commits to WebKit.

Safari 14.1:

• api.Body.formData (Mark Request.p.formData partial in Safari #6616, Document Body.p.formData as always rejecting #6619, https://webkit.org/b/215671, https://trac.webkit.org/r266087)

@apple-web-evangelist FYI. If there's anything that could be done to make it easier to update Safari data for each release, that would be great :D