web/web_ir_actions_act_window_message/readme/USAGE.md

Depend on this module and return

{
    'type': 'ir.actions.act_window.message',
    'title': _('My title'),
    'message': _('My message'),
    # optional title of the close button, if not set, will be _('Close')
    # if set False, no close button will be shown
    # you can create your own close button with an action of type
    # ir.actions.act_window_close
    'close_button_title': 'Make this window go away',
    # Use HTML instead of text
    'is_html_message': True,
    # this is an optional list of buttons to show
    'buttons': [
        # a button can be any action (also ir.actions.report.xml et al)
        {
            'type': 'ir.actions.act_window',
            'name': 'All customers',
            'res_model': 'res.partner',
            'view_mode': 'form',
            'views': [[False, 'list'], [False, 'form']],
            'domain': [('customer', '=', True)],
        },
        # or if type == method, you need to pass a model, a method name and
        # parameters
        {
            'type': 'method',
            'name': _('Yes, do it'),
            'model': self._name,
            'method': 'myfunction',
            # list of arguments to pass positionally
            'args': [self.ids],
            # dictionary of keyword arguments
            'kwargs': {'force': True},
            # button style
            'classes': 'btn-primary',
        }
    ]
}

You are responsible for translating the messages.