How is it possible to patch Bitcoin? How can someone patch Bitcoin? 

I don't understand, if someone wants to change or add code to the Bitcoin repo. I've read there is a few people that have access to publish new code (?). Why are those people trusted? And how would they publish the new code so every node gets the updated version? Does every node download it from some central server? Or does someone push it? In both cases, it doesn't seem decentralized.
How can someone patch Bitcoin?



git clone
do changes
make &amp;&amp; run



  Why are those people trusted?


You have a right not to trust them


  And how would they publish the new code so every node gets the updated
  version?


Node owners have a right not to upgrade to "referal" version


  Do every node download it from some central server?


No. Everyone have a right to change everything in his own copy of sources.


  Or do someone push it?


No.


  In both cases, it doesn't seem decentralized.


The development of "referal" software is not decentralized.