Notes about the T3X file extension:
Incorrect file associations could be the result of underlying issues within your PC system. As such it is highly recommended to scan your PC for invalid registry entries, unused processes and other unfavourable system settings to identify slowdown issues.
The T3X file type is primarily associated with 'TYPO3' by The TYPO3 Association. The TYPO3 project is a free CMS framework released under the GPL. The .T3X file is an extension of the framework.