Brake Line Brackets in Engine Bay?

Can anyone tell me how these brackets are held on or how to release them? In the last picture you can see I was able to remove one and it has a stud behind it but no nut to loosen on the front side....

Any tips for removing the actual lines from the brackets? Pry the little tabs open with a screw driver then pull but alas I have broken a few already.

https://ibb.co/rpMgHVw
https://ibb.co/j4ndSnw
https://ibb.co/pzsctcH
https://ibb.co/Zf1Pmms

 

https://ibb.co/zFrFQC8
https://ibb.co/x59G7zG

This one is completely off. I suppose the plastic clips down onto the stud somehow. Not sure if there's a way to remove without breaking them as this one doesn't want to go back on tight. I might try to reuse it by threading a bolt on the stud to hold it or order some new ones.