A permission controls whether a user can perform a specific activity.
For more information regarding Standard Permissions, please refer to DevTest documentation in the link below:
https://docops.ca.com/devtest-solutions/10-3/en/administering/security/access-control-acl/standard-permissions/
 

Which permission enables DevTest users to access the option 'Tests' under Monitor in the DevTest Portal?

All supported DevTest releases.

The 'Report Administration' permission needs to be assigned to users Role.
For more information regarding this permission please refer to the link below:
https://docops.ca.com/devtest-solutions/10-3/en/administering/security/access-control-acl/standard-permissions/#StandardPermissions-ReportAdministrationPermission