MCPBot is finally dead, and so goes with it every old version of ForgeGradle. Hope you're not maintaining any 1.7-1.12 mods anymore (or, god forbid, 1.6)! Because if you do, nobody will help you, and if you ask you will be banned from all official Forge channels. Fun fun fun. Game over.
...Or not. Someone asked ArchiveBot to rescue the MCPBot exports, and a WARC file containing a seemingly complete archive is available for download. And, these old ForgeGradle versions download mappings over plain HTTP, not HTTPS!
I maintain Ears, a mod available for too many versions of Minecraft, and it uses old versions of ForgeGradle to build the 1.6, 1.7, 1.8, 1.9-1.11, and 1.12 ports. Because reengineering these old versions of ForgeGradle is a huge goddamn wa