[Grok-dev] AddForm Mystery Number

[Steve Schmechel]

This may be more of a FormLib or zope.app.file question, but I came
across it while working with the Grok how-to

"Handling file uploads with zope.app.file and zope.file"
http://grok.zope.org/documentation/how-to/uploading-file

When looking at the view created by:

class Upload(grok.AddForm):
    grok.context(FileContainer)
    form_fields = grok.AutoFields(zope.app.file.interfaces.IFile).select('data')

you can see that the HTML for the submit button is generated like:
<input type="submit" id="form.actions.4164642066696c65" name="form.actions.4164642066696c65" value="Add file" class="button" />

Where does the "magic number" 4164642066696c65 come from?

Instead of moving to a separate page to upload a file, I want to include
file selection on the "Index" page along with the file listing.

I am able to post to the "upload" view from my listing page as long as
my submit button includes "form.actions.4164642066696c65".

This number seems to be very static.  I've restarted the server, created
new root applications, accessed the site from other clients.  It all works
great, but I am fearful it will one day stop working because I did not
understand the meaning of this number.

Other grok.AddForm views do not generate this type of submit button.
They look like:
<input type="submit" id="form.actions.add" name="form.actions.add" value="Add" class="button" />

Can someone please shed some light on this number?
Should I not post to an auto-generated AddForm view from another view?

Thank you,
Steve