In order for context and its tools to be able to locate files in the tds compliant tree you need to copy 'contextcnf.lua' to 'texmfcnf.lua'. There is a fallback to 'contextcnf.lua' when no 'texmfcnf.lua' is found. You can have multiple 'texmfcnf.lua' files which means that you can overload global settings.