blob type should not be all lowercased...

[jimmywarting]

Can we complement this list with something like:

const type     = 'Multipart/form-data; Boundary=ABC'
const expected = 'multipart/form-data; boundary=ABC'
new Blob([], {type}).type === expected

From what i understand (in this thread), the mimetype and keys (in mime/type; key=value) should be lowercased but the value shouldn't?
you loose valuable information by doing this... eg:

const res = new Response(new FormData())
const blob = await res.blob()

// multipart/form-data; boundary=----WebKitFormBoundaryLt9YzkQfzVBgA5nL
const expected = res.headers.get('content-type')

// multipart/form-data; boundary=----webkitformboundarylt9yzkqfzvbga5nl
const actual = blob.type

actual === expected // should be true.