That would be Adam Back and Greg Maxwell.
Please explain in what way Adam Back has any say about anything that happens in Bitcoin Core. He is not a contributor, and AFAICT, never has been. He is not a member of the
"team", he doesn't have commit privileges, he doesn't even participate in developer discussions on the IRC channels nor in the weekly developer meetings. So how, exactly, does Adam Back "lead" Bitcoin Core? If anything, I would say that the leader of Core is Wladimir as he is the release maintainer, usually the one who merges everything, chairs the weekly dev meetings, etc.
Hi achow, always respect your answers and insight. If a number of contributors not listed also help decide what goes into Core, how is it that the Hong Kong agreement resulted in a "proposal" by contributors? Does this mean that contributors may have an avenue for opening ideas but a higher layer still calls the shots?
Some contributors (not all, in fact, only 4 IIRC), were at the Hong Kong meeting and are the ones who made the proposal. Any individual can make a proposal, but that does not mean that everyone who works on the project frequently will think that it is a good idea and that everyone will agree to accept the proposal and implement it. There is no "higher up" but rather a group consensus decision.
Where is there documentation on the leadership/direction of "Core". I (think I) understand that decentralisation means just that there is no such thing, but to my uninitiated mind, it seems more a (non-deliberate) lack of transparency rather than decentralisation.
There isn't documentation really, and there really isn't a leadership structure. You can see who is considered a part of the "team" at
https://bitcoincore.org/en/team/ but the team does not included everyone who contributes, just those who do so fairly frequently. The leadership consists of the three maintainers as they are the ones who merge everything (and Sipa who has commit access but isn't a maintainer) and I suppose you could say Wladimir is the leader as he is the release maintainer.
Who got to choose who became "Core"? Were they self-appointed?
Basically. People who contribute to Core frequently became noticed by other contributors, and over time, became associated with "Core" as a "Core dev". The only people who were "appointed" were the three maintainers, and only because they were basically doing the position that they were given for a while before they were actually given the titile. E.g Wladimir was setting out release schedules, release TODOs, release notes, and making releases themselves for a while before Gavin officially gave him the title. Jonasschnelli was submitting wallet and GUI pulls and reviewing other wallet and GUI pulls for a long time and he basically became the final say on wallet and GUI related stuff for them to be merged or not until Wladimir eventually made him the wallet and GUI maintainer. The same thing happened with MarcoFalke for him to become the QA maintainer.