This is Lightning for PowerPC Mac OS X. (Unofficial build)
Lightning is already distributed with Tenfourbird. These xpi files are distributed for re-installation.
You can check integrity of files by RIPEMD160 or SHA512 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.
source and patches are same as Tenfourbird 38.1.0.