Risk Management is the process of identifying, assessing, and responding to risks that may affect the achievement of the enterprise's objectives. Risk Management involves balancing positive and negative outcomes resulting from the realization of either opportunities or threats. Reference: The TOGAF Standard | The Open Group Website, Section 3.3.3 Risk Management.

Explanation
https://pubs.opengroup.org/architecture/togaf8-doc/arch/chap03.html
The chart that you have provided is a Gantt chart that shows the tasks and timelines of a TOGAF project. It illustrates the concept of phased development of an Enterprise Architecture, which is one of the key principles of the TOGAF Architecture Development Method (ADM). The ADM is a cyclic process that consists of nine phases, from Preliminary to Architecture Change Management1. Each phase has a specific purpose, scope, inputs, steps, and outputs, and produces a part of the Enterprise Architecture. The phases are executed in a sequential order, with some iterations and feedback loops, to ensure that the architecture is consistent, complete, and aligned with the business requirements and objectives. The phases also have a limited fixed duration, which is determined by the complexity, scope, and resources of the project. This helps to manage the expectations, risks, and costs of the architecture development, and to deliver the architecture in a timely and effective manner23.

Based on the illustration, the phase of the ADM labeled as item 2 is the Implementation Governance phase. This phase provides architectural oversight for the implementation. It ensures that the implementation project conforms to the architecture. It also provides a framework for monitoring and managing the implementation.
The Implementation Governance phase involves the following activities:
Finalizing the Architecture Roadmap and the supporting Implementation and Migration Plan Assigning an Architecture Board to oversee the implementation Establishing Architecture Contracts with the implementation partners Reviewing and approving the implementation project plans and deliverables Performing Architecture Compliance reviews to ensure alignment with the architecture Performing Architecture Audit reviews to ensure quality and performance of the architecture Resolving any architecture issues or change requests that arise during the implementation Maintaining the architecture lifecycle and ensuring its continuity The Implementation Governance phase is essential for ensuring that the architecture is realized as intended and that it delivers the expected business value and outcomes.

The purpose of Enterprise Architecture is to guide effective change by providing a coherent and consistent view of the enterprise's current and future state, as well as the roadmap and principles for achieving it.
Enterprise Architecture helps to align business and IT strategies, optimize resources and investments, reduce complexity and risks, enhance agility and innovation, and deliver value to stakeholders. Reference: The TOGAF Standard | The Open Group Website, Section 1.3 Executive Overview.