Educate people how to validate TBB 3.X+ (The deterministic ones)
(don't know the component)
Get GPG and download the signature to validate the bundle, which is signed with this key.
It will be:
Get GPG, download the checksum file, download the signature for the checksum file, which can be signed by a bunch of people, to validate the checksum file. Calculate the sha256 hash, which will require to install software on Windows (correct me if I'm wrong), of the bundle and check if the hash appears in the checksums file.