The Template Toolkit (TT) is a template language and processing engine written in Perl. TT2 is the current stable version (v2.20). If you're not an existing user of TT2 then this site will probably be of little interest to you at this time.
TT3 is a major new version of the Perl Template Toolkit. It's been in development for, ahem, some time now. It's a complete re-design and re-write from the ground up.
TT3 is in a pre-alpha release state. Most of it works, but there are plenty of bits missing and rough edges to clean up. You can play with it, but I wouldn't put it in any mission critical applications at this point. Caveat Templator.
For the latest information, please consult the Status.pod file in the source code repository.
Enlighten me! Let me read the Status.pod!