I can do fixes but some times get stumped. Can anyone tell me what this is? It looks like a quick release on the flexible tubing to the side spray.

Mom has trouble pulling out the side spray on her kitchen sink. I bought smaller OD nylon weave tubing that should create less drag. Ultimately, she needs a new faucet with a pull down spray, but we do things on mom's time. She resents decisions being made for her. I'm down, just want to make it workable in the meantime.

It's a bitch to get at, so if that's a quick release, that would be smarter than trying to take the nut off at the top.