For those that have customized their vSphere Client Login UI using the instructions here and here, it looks like the process can not be applied to the vSphere 6.7 release. From what I can tell, it looks like we have now consolidated the various WAR files into a single file /usr/lib/vmware-sso/vmware-sts/webapps/ROOT.war. The original contents of the websso directory, which pertains to the UI customization, is now located here. This was a fairly minor change, but something to be aware of and for details on how to persist your configuration changes, please see the instructions below.
UPDATE (11/19/22) - As of vSphere 8, the webapp WAR file is now located in /var/lib/sso/webapps/ROOT.war
Disclaimer: This is not officially supported by VMware. If you decide to enable this, please use at your own risk and ensure you backup all original files in case you need revert back to the original configuration.
As part of looking into this, I also had some fun incorporating a cool little animated login page directly into the vSphere UI which I had shared on Twitter yesterday. Stay tuned for more details on #vYetti 🙂