As one of its most important properties and a key selling point, Bitcoin is not controlled by any government, (central) bank or company. Nor is there even an active inventor to call the shots, as is the case in many other open-source projects. But that doesn’t mean the peer-to-peer electronic cash system is not governed by humans at all.
Many attribute this governance role to the Bitcoin Core development team. This is a misguided attribution, however. While Bitcoin Core developers may have an influential position, Bitcoin is really governed by only two groups of people: users and miners.
Bitcoin itself is essentially nothing but a protocol; a language shared by computers. And importantly, Bitcoin is an “open” protocol: there are no gatekeepers or requirements to become part of the Bitcoin network, other than following this protocol.
Anyone with the required skill-set can develop software to follow the protocol. But the easier option, of course, is to simply download and run software developed by others.
There are currently several Bitcoin software implementations to choose from, as well as forks (near copies) of these implementations. The most used of these is probably still Bitcoin Core, the software stack that evolved from Bitcoin