Tenfourbird ist inoffiziell Build von Mozilla Thunderbird für PowerPC-basierten Mac OS X.
This is Enigmail for PowerPC Mac OS X. (Unofficial build)
You can check integrity of files by SHA1 hashes. It also signed by OpenPGP key of t_mrc-ct[at]users.sourceforge.jp. The public key could get from here or OpenPGP Keysever.
This build based on enigmail-1-7