If you have installed Fedora 19 Beta on your computer, you may have noticed that there is a tbot entry in your GRUB.
This is just a bug and will be fixed for Fedora 19 final version.
Trusted Boot (tboot) is an open source, pre-kernel/VMM module that uses Intel Trusted Execution Technology (Intel TXT) to perform a measured and verified launch of an OS kernel/VMM.
Tbot uses Intel Trusted Execution Technilogy (Intel TXT). To boot in tbot, you need to have a chip on your motherboard called Trusted Platform Module (TPM). If you don’t have it, nothing will happen.