many2one_reference_integer

This is one of the smallest widgets in Odoo. It subclasses the integer widget and replaces a single getter:

export class Many2OneReferenceIntegerField extends IntegerField {
    get value() {
        const value = this.props.record.data[this.props.name];
        return value ? value.resId : false;
    }
}

A many2one_reference field arrives in the browser as an object carrying a resId and a display name. The standard integer widget would not know what to do with that object. This widget reaches in, takes the id, and hands it to the integer rendering it inherited.

Everything else, including formatting and edit behavior, comes from the integer widget unchanged.

This is a technical screen widget. It exists so that developers and administrators looking at Odoo's own plumbing, such as the model and field configuration screens, can see the actual database id rather than a friendly label.

If you are considering it for a business-facing form, ask what problem the id solves. Users almost never want a record id. They want the record. The only common legitimate case is a support or integration screen where someone needs to quote an id to a system that does not speak Odoo.

Showing the raw id, with no companion field needed:

<field name="res_id" widget="many2one_reference_integer"/>

Compare with the picker version, which does need one:

<field name="res_model" invisible="1"/>
<field name="res_id" widget="many2one_reference"/>

Its sibling many2one_reference throws a hard JavaScript error when the companion model field is absent from the view, because it cannot resolve a relation without it. This widget never resolves a relation at all, so that failure mode does not exist.

That makes it the safe choice in two situations. First, on a generic list of mixed records where adding the model field to the view is impractical. Second, as a diagnostic: if a form is failing with the model_field must be in view error, temporarily swapping in this widget renders the row and lets you see what the underlying data actually holds.

The price is that the user sees 417 where they wanted SO0142. This is a debugging and administration widget, and it reads like one on any screen a non-technical user opens.

No change. The registration is identical on the 20.0 branch: same component shape, same supported type, still no options. It is still used exactly twice, in the same file.