There is an wizard action in snailmail module, snailmail_letter_format_error_action​, the complete path is /snailmail/wizard/snailmail_letter_format_error_views.xml​. and this action is being called from a js​ function is called _onClickFormatError​. and this function is defined in the events like, 

var ThreadWidget = require('mail.widget.Thread');

ThreadWidget.include({

    dependencies: ['bus_service'],

    events: _.extend({}, ThreadWidget.prototype.events, {

        'click .o_thread_message_snailmail_missing_required_fields': '_onClickMissingRequiredFields',

        'click .o_thread_message_snailmail_credit_error': '_onClickCreditError',

        'click .o_thread_message_snailmail_trial_error': '_onClickTrialError',

        'click .o_thread_message_snailmail_no_price_available': '_onClickNoPriceAvailable',

        'click .o_thread_message_snailmail_format_error': '_onClickFormatError',

        'click .o_thread_message_snailmail_unknown_error': '_onClickUnknownError',

    }),

And i searched the class name o_thread_message_snailmail_format_error​, but no luck. How odoo call this js function via click event without a class name in XML file? Plese help me understatnd this?