The T file extension is also known to be integrated in Microsoft Corporation's Notepad text files in the German version. By default, the T file extension is used in this specific version; it creates the unbennann.t that means 'noname' text file. The T file extension may be used in text files of Notepad giving the meaning as text files to the created document in German.
The T file extension is associated with Paradox, a relational database management system sold by Corel Corporation, which is part of some editions of Corel WordPerfect Office suite. The .t files were used in some very old version of Corel Paradox for databases.