Adding entries to FieldList

[Lopkop]

Actual Behavior

This is my fields and html code:

class FileForm(FlaskForm):
    filename = StringField('Filename')
    value = TextAreaField('Paste', validators=[DataRequired()])


class PasteForm(FlaskForm):
    paste = FieldList(FormField(FileForm), min_entries=1)
    submit = SubmitField('Create paste')

{% for field in form.paste %}
<p>
    {{ field.filename(placeholder='Filename') }}

</p>
<p>
    {{ field.value(wrap='off') }}
</p>
{% endfor %}
<form>

I found on reddit, that format is <form_variable_name>-<id_number> for creating new entries. So I added it, but I just got new blank form in FieldList.
First question: Why there is no information about this in documentation?
Second question: Why below html just adds blank form to FieldList with blank filename and value ? (see result below)

<input name="paste-1" type="text">
<textarea name="paste-1"></textarea>

This is an output if I am filling all 2 forms:
[{'filename': 'test.py', 'value': "print()", 'csrf_token': None}, {'filename': None, 'value': None, 'csrf_token': None}]
As you can see only first form has values

What I expected to see?

1. Documentation about this feature
2. filename and value filled with values

Environment

• Python version: 3.11.9
• wtforms version: 3.1.2