[ssl-3]

I considered the small "o". But the precedent for US government TLAs seems to be to capitalize the whole thing: https://www.justice.gov/nsd-ovt/us-government-acronym-list

[Retric]

Capitalizing everything is the new direction, but I doubt it’s going to stick around. There’s a long legacy of DoD vs DOW, for a current military example that wasn’t updated: https://dodtap.mil/dodtap/app/about/DoDTAP

Here the DoD pattern makes it clear what part of the larger acronym is representing.