2822upd-04 field-name vs. line length and obs-optional

2822upd-04 section 3.6.8 reads in part:

   field-name      =   1*ftext

That specifies unlimited length, which conflicts with line length limits
specified in section 2.1.1.

   field-name      =   1*77ftext

would conform to the lower recommended limit. [for reference, the
longest field name that I know of defined in a published RFC is
Delivery-Report-Content-Reported-Recipient-Info (47 characters)
defined in RFC 987.]

2822upd-04 section 4.5.8 reads:

4.5.8.  Obsolete optional fields
   obs-optional    =   field-name *WSP ":" unstructured CRLF

[off-topic] unlike most sections, this one lacks vertical whitespace between
section heading and text.

This one probably needs an obs-field-name as RFC 733 permitted space/tab
within (but not at the start of, for obvious reasons) a field-name (and it
is occasionally necessary to parse old messages).