In the Chapter "2.1.1. Java Adapter Config" of Securing Applications and Services Guide, there are missing explicit OPTIONAL/REQUIRED markers from some adapter options.
With most of them the optional character is implied (by stating default value or from other context) but not with all of them.

• autodetect-bearer-only
• proxy-url
• always-refresh-token (not obvious if OPTIONAL or REQUIRED)
• register-node-at-startup
• register-node-period
• token-store
• principal-attribute
• min-time-between-jwks-requests
• public-key-cache-ttl