Short Explanation: To meet the requirements, the DevOps engineer should update the SAML assertion to pass the user’s team name, update the IAM role’s trust policy to add an access-team session tag that has the team name, create an IAM permissions boundary in each account, and for each CodeCommit repository, add an access-team tag that has the value set to the name of the associated team.

Updating the SAML assertion to pass the user’s team name allows the DevOps engineer to use IAM tags to identify which team a user belongs to. This can help enforce fine-grained access control based on the user’s team membership1.

Updating the IAM role’s trust policy to add an access-team session tag that has the team name allows the DevOps engineer to use IAM condition keys to restrict access based on the session tag value2. For example, the DevOps engineer can use the aws:PrincipalTag condition key to match the access-team tag of the user with the access-team tag of the repository3.

Creating an IAM permissions boundary in each account allows the DevOps engineer to set the maximum permissions that an identity-based policy can grant to an IAM entity. An entity’s permissions boundary allows it to perform only the actions that are allowed by both its identity-based policies and its permissions boundaries4. For example, the DevOps engineer can use a permissions boundary policy to limit the actions that a user can perform on CodeCommit repositories based on their access-team tag5.

For each CodeCommit repository, adding an access-team tag that has the value set to the name of the associated team allows the DevOps engineer to use resource tags to identify which team manages a repository. This can help enforce fine-grained access control based on the resource tag value6.

The other options are incorrect because:

Creating an approval rule template for each team in the Organizations management account is not a valid option, as approval rule templates are not supported by AWS Organizations. Approval rule templates are specific to CodeCommit and can only be associated with one or more repositories in the same AWS Region where they are created7.

Creating an approval rule template for each account is not a valid option, as approval rule templates are not designed to restrict access to modify branches. Approval rule templates are designed to require approvals from specified users or groups before merging pull requests8.

Attaching an SCP to the accounts is not a valid option, as SCPs are not designed to restrict access based on tags. SCPs are designed to restrict access based on service actions and resources across all users and roles in an organization’s account9.