I have seen these before, but for the life of me I cannot seem to recall what they are called or what they’re for.
Google search - especially image search, where I’m trying to bring up similar items - is now a total potato and seemingly capped at one screen of results in a secure and sanitized browser.
db13w3 has an alternative configuration with coax instead of power pins, used to be used for computer monitors. Even has it’s own wiki entry.
https://en.wikipedia.org/wiki/DB13W3
Maybe that’s why it’s familiar?