What is the intersection comprised of?
Elegant, maintained, useful software.
Where does it reside?
A mystery. Although case studies may glean some insight.
Sqlite:
https://ghostarchive.org/archive/wpteG
In a world of people obsessed by turning the tiniest idea into something profitable, Dr Richard Hipp's best-known software stands out for two reasons - he actively disclaims copyright in it; and at a time when multi-megabyte installations are booming, he has a self-imposed limit on the size of his product: 250KB. And he's stuck to both aims. "I think we've got 15 kilobytes of spare space," he says of the headroom left in the code.
https://sqlite.org/codeofethics.html
The founder of SQLite, and all of the current developers at the time when this document was composed, have pledged to govern their interactions with each other, with their clients, and with the larger SQLite user community in accordance with the "instruments of good works" from chapter 4 of The Rule of St. Benedict (hereafter: "The Rule"). This code of ethics has proven its mettle in thousands of diverse communities for over 1,500 years, and has served as a baseline for many civil law codes since the time of Charlemagne.
ffmpeg, qemu:
https://ffmpeg.org/developer.html#toc-Code-of-conduct
Be friendly and respectful towards others and third parties. Treat others the way you yourself want to be treated.
Be considerate. Not everyone shares the same viewpoint and priorities as you do. Different opinions and interpretations help the project. Looking at issues from a different perspective assists development.
Do not assume malice for things that can be attributed to incompetence. Even if it is malice, it’s rarely good to start with that as initial assumption.
Stay friendly even if someone acts contrarily. Everyone has a bad day once in a while. If you yourself have a bad day or are angry then try to take a break and reply once you are calm and without anger if you have to.
Try to help other team members and cooperate if you can.
The goal of software development is to create technical excellence, not for any individual to be better and "win" against the others. Large software projects are only possible and successful through teamwork.
If someone struggles do not put them down. Give them a helping hand instead and point them in the right direction.
Finally, keep in mind the immortal words of Bill and Ted, "Be excellent to each other."
https://smartbear.com/blog/fabrice-bellard-portrait-of-a-super-productive-pro/
Bellard seems to balance nicely between extremes that threaten productivity. His techniques are modern without being faddish, and careful, yet not neurotic. While he moves every few years into new and fertile unconquered territory, he exercises patterns that have served him well over and over: cleanly-styled C, data compression, numerical methods, signal processing, pertinent abstractions, media formats, open-source licensing, and “by-hand parsing.”
Bellard doesn’t appear to promote himself—he politely declined to be interviewed for this profile, for example—but others enthusiastically adopt his creations. Among the 654 Copyright notices QEMU 0.13.0 source code embeds, 216 are his. To put that another way: He was successful enough with QEMU during its first few years to entice others to put in over twice as much work (by this crude measure) as he has!
Shedding the self seems to be a common denominator... what comes to mind is "let the Lord worketh through ye"
Matthew 5:14-16 GW
“You are light for the world. A city cannot be hidden when it is located on a hill. No one lights a lamp and puts it under a basket. Instead, everyone who lights a lamp puts it on a lamp stand. Then its light shines on everyone in the house. In the same way let your light shine in front of people. Then they will see the good that you do and praise your Father in heaven.
Philippians 2:12-13 GW
My dear friends, you have always obeyed, not only when I was with you but even more now that I’m absent. In the same way continue to work out your salvation with fear and trembling. It is God who produces in you the desires and actions that please him.