Open digital public infrastructure requires community governance to ensure accountability, sustainability, and robustness. However, open source projects often rely on centralized decision-making, and the determinants of successful community governance remain unclear. This study analyzes 637 GitHub repositories to trace the transition from founder-led to shared governance. Specifically, we extract institutional roles, actions, and accountability signals from versioned project charters (GOVERNANCE.md) to document the trajectory toward community governance. Using a semantic parsing pipeline, we categorize elements into broad role and action types. We find that roles and actions increase and regulation becomes more balanced, reflecting an increase in governance scope and differentiation over time. Communities grow by layering and improving accountability rather than changing tone. As the transition to community governance matures, projects further regulate ecosystem-level relationships and define project oversight roles. This study provides a scalable pipeline for tracking the growth and evolution of community governance systems from founder ownership, a fundamental tenet of open source software.