How do HTML5 forms lower to prompts?

Element     Required?   free-form?      ngrams      editable?                   options             multiple?   Notes
text/search @required   Yes             from page   !@readonly || !@disabled    ref'd by @list      No
radio       @required   No              -           ...                         inputs sharing name No          <label> refers to individual options instead.
checkbox (1)@required   No              -           ...                         Yes/No/synonyms     No
Checkbox    @required   No              -           ...                         inputs sharing name Yes         <label> refers to individual options instead.
submit      No          No              -           Yes                         None                No          Target read as METHOD ACTION, labelled by @value or innertext.
<select>    @required   No              -           !@readonly || !@disabled    child <option>s     @multiple
<textarea>  @required   Yes             from page   !@readonly || !@disabled    None                Yes
button      UNSUPPORTED (requires JavaScript)
<legend>    Yes (shows) No              -           No                          None                No          Serves purely as a label.
<output>    No          Yes             None        No                          None                No          Requires JS, but it'd be nice to have an alternative.
password    @required   Yes             None        !@readonly || !@disabled    "New password"      No          Obscured in output.
reset       No          No              -           Yes                         None                No          Links to current form (unfilled).
color       @required   No              -           !@readonly || !@disabled    CSS3 color keywords No          Benefits from a system dialog, given it's inherantly a visual concept.
date        @required   Yes             day/month/year/ago      ...             "Today"             No          Reprocessed into ISO date.
datetime-local @requiredYes             day/month/year/hour/minutes     ...     "Now"               No          Reprocessed into ISO date.
email       @required   Yes             @/./alphadigit/etc      ...                                 @multiple   spaces removed, instantiates punctuation
file        @required   Yes             (custom recognizer)     ...                                 @multiple   Benefits from system dialog
month       @required   Yes             month/year              ...             "This month"        No          Reprocessed into ISO date
number/range@required   Yes             digit       ...                                             No
tel         @required   Yes             digits (ignore -)       ...                                 No
time        @required   Yes             digits/am/pm        ...                 "Now"               No          Reprocessed into ISO time.
url         @required   Yes             browser history/alnum/punctuation   ... bookmarks           No          spaces removed, instantiates punctuation, infers https
week        (AS PER date, reprocessed)

Attributes:
@value - prefilled value, if set removes from initial prompts.
@readonly/@disabled - disables editting, removes from initial prompts.
@size - IGNORED
@maxlength - postprocessing validation
@min/@max - postprocessing validation
@multiple - sets this prompt to repeat until user says "next".
@pattern - gives hint as to punctuation to expect, postprocessing validation.
@placeholder - fallback for <label>
@required - adds to initial prompts. If none are required it'll consider all inputs required.
@step - prostprocessing validation.
@autofocus - triggers this form mode.
@height/@width - IGNORED
@list - sets named options.
@autocomplete - IGNORED, always autocompletes.
Be nice to let inputs their own ngrams/vocabulary!

@formaction, @formenctype, @formmethod, @formtarget - where to send form data.
@formnovalidate - disables postprocessing validation.
Be nice to let forms link to newline seperated "phrases" which can be used to fill in multiple inputs simultaneously, more conversationally.