Unfortunately a fairly recent naming collision has caused this XBlock to no longer load. Since this was an unsupported, experimental XBlock, we have removed ProfileXBlock from the requirements in edx-platform, and it will no longer be available on edx.org (see https://github.com/edx/edx-platform/pull/14573).
If members of the open source community wish to continue using this XBlock, details of the naming collision can be seen in https://openedx.atlassian.net/browse/TNL-6533; hopefully the fix is straightforward.