There are a couple of design documents put under wiki while they are useful to users and need to be updated later. Create patches to move them into the source folder with restructured text format (RST).
These documents are candidates, the decided list would be updated later:
• Code Generation With Jinja2
• Cooperative Scheduling Rules
• Non-secure Client Management
• Non-Secure Interrupt Handling
• Secure Partition Interrupt Handling
• Service IPC compatibility - Attestation
• Trusted Boot
• Trusted Firmware-m Isolation Level 2
• Twin-cpu
• Uniform Secure Service Signature