From any page, click on your username/nickname located at the upper right corner. In the dropdown menu click on settings. You can also click on this link while logged into your account: https://wearereformed.com/community/settings
At the bottom left corner is the Security link.
Clicking on that link will bring you to the security page and will display all Active Sessions including the Current Active Session. You can then terminate individual sessions, all sessions, or in the event of an account breach the Global Logout.
Performing a Global Logout "Clears current cookie session, terminates all sessions, revokes developer tokens, and invalidates any email confirmation or password reset emails."