Where does headline data end for the purpose of `org-adapt-indentation´ == ´headline-data

[Farblos]

I like the idea of org-adapt-indentation being ´headline-data:
  When this variable is set to ‘headline-data’, Org only adapts the
  indentation of the data lines right below the headline, such as
  planning/clock lines and property/logbook drawers.

However, I find the resulting indentation behavior confusing.  Before
reporting bugs, I'd like to know where the headline data ends.  I'd
expect that the first blank (or whitespace-only?) line after a headline
would end the headline data.

Below are some examples where to I think headline data expands ("<==" 
pointing to point, underscore indicating trailing blanks).  Probably 
somebody could correct or confirm.

Thanks!

** Headline 1
<== in headline data ==

** Headline 2
   :properties:
   <== in headline data ==

** Headline 3
   :properties:
   :custom_id: foo
   :end:
   :logbook:
   clock: [2023-06-08 Thu 12:34]--[2023-06-08 Thu 12:36] =>  0:02
   :end:
   <== in headline data ==

** Headline 4
   :properties:

<== out of headline data

** Headline 5
   :properties:
___
<== out of headline data (previous line containing three blanks)