We also see limited upside from community contributions - the number of people who can meaningfully work on a WebKit browser is small (from our experience hiring), and most of them already work at Apple or Kagi. Meanwhile, managing an open source codebase of this size would add real strain to our small team.
The plan is however to open source when Orion is self-sufficient (business model of Orion is you are the customer and can pay for it - like we used to pay for browsers 20 years ago before advertisers started paying for our browsing), meaning it can sustain its own development independent of Kagi Search. I want to take the opportunity to thank all people who supported the Orion browser vision [1]. We're not there yet but recent 1.0 launch and expanding to Linux are steps in that direction. And on Jan 1st this year we began development of Orion for Windows (HN exclusive yay!).
I understand this is unsatisfying to people who want source access now. It's a tradeoff we've made deliberately, not something we're hiding behind.