Transparency and explainability of high-risk AI systems are essential for deployers to be able to understand the AI system's logic, to use it correctly, and to explain to affected individuals with respect to the use of AI systems. Without such understanding, the deployer would not be able to exercise control over the system and effectively attribute actions to it and relevant persons. It is therefore required that providers design the AI systems in a transparent and explainable manner, which is critical for deployers to fulfil their legal obligations. Providers should develop and maintain technical documentation explaining the internal logic and external behaviour of AI systems. High-risk AI system providers should ensure that such documentation is made available to the competent authorities and deployers upon request.