Simply browse to http://CUCM-IP-address:6970/jabber-config.xml
Remember that TFTP files are not configuration changes to the configuration database replicated by the publisher to the subscriber. Likely, your publisher or the server you are checking is not a TFTP server. You need to upload jabber-config.xml to all TFTP servers.
If it does exist when you check in OS Administration > Software Upgrades > TFTP File Management, then you need to restart Cisco Tftp for the change to take effect.
Check the installation and configuration guide for more information: