TenFourFox PPC browser has run atop the Gecko engine until now and apparently that will be phased out with TFF 45.9. This will be the final ESR release built on Gecko. In June, the new TFF will have its own rendering engine, Firefox Parity Release, to keep the port to Mac OSX PPCs up to date. Just like with the Pale Moon browser release, its going to branch off on its own development path separate from FF's ESR source code.
