Hello there,
does your question address SSO or customization?
For customization I'd recommend checking this very useful DevCentral topic which helped me a lot when tuning customers logon pages:
https://devcentral.f5.com/s/articles/Advanced-Customization-Quick-Start-Guide-for-Modern-Template-APM-15-1
There's also config templates available in attached files.
Abous SSO logic, there's so many options available that it's hard to guess which specific one is in use. Higly doubt F5 would share such information as well as it might be something sensitive.