❤️ HealthKit & HomeKit
What it is
HealthKit is the shared health database (steps, workouts, heart rate) apps can read/write with granular per-type permission. HomeKit controls smart-home accessories. Both are 'sensitive' entitlements with dedicated sections in the App Review Guidelines (5.1.3 for health) and extra reviewer scrutiny.
When you need it
HealthKit: fitness trackers, sleep apps, workout loggers that want to read or contribute to Apple Health. HomeKit: apps controlling HomeKit-certified accessories. Don't enable either speculatively — an entitlement with no visible feature invites rejection questions, and unused HealthKit entitlements get flagged.
Setup, review rules & privacy labels — Pro
Per-stack setup instructions, App Review rules, and privacy-label mapping are part of the full reference.