You may determine all the global capabilities assigned to a user based upon global role assignments (either directly or via group assignments).
Steps
1. Sign in as a user with at least the Security Administrator capability global role assignment.
2. Go to MANAGE > Users in the banner.
3. Right-click a user and select Show Global Capabilities.
Example
Sign in as an Administrator.
Go to MANAGE > Users in the top banner.
Right-click Stu and you have context menu options:
Select Show Global Capabilities: