One fix, for issue #61.
A graphics mode the engine cannot run no longer kills every launch. An environment set to D3DMetal on an engine that has the files but no licence accepted for them died at each launch with "missing: d3dmetal renderer (optional component not installed?)", and only a new environment got you out. Now such an environment starts with DXMT and says why in the log. The licence is asked for in context whatever selected D3DMetal, with a "Play with DXMT" way out. Fix recipes no longer set a mode the engine cannot serve. The environment's settings show the current mode and what programs start with instead. If you hit this on 0.8.4, pick DXMT under Graphics in the environment's settings, or accept Apple's licence there.