CTF is a lightweight debugging format that provides information about C types and the association between functions and data symbols and types. It is designed to be embedded in ELF files and to be very compact and simple.
The current version of the CTF specification is V3. There is an effort in progress to evolve the format into a V4 in order to provide better support for type specification, and other domains like on-line backtracing and ABI analysis. This effort is public and open to anyone wanting to participate; please subscribe to the mailing list (details below) if you want to help or to follow the discussions.
The CTFv3 file (ELF section) format specification is here (texinfo, PDF).
There is no documentation for the libctf library yet: the header file is here.
Right now there is only one list associated with CTF, email@example.com, covering all matters CTF-related, from future format revisions through changes to producing and consuming programs.
Subscribe by sending a mail to firstname.lastname@example.org.
This is a non-exhaustive list of software that implements CTF data (either generating or consuming it).