Normally a subsystem contains some documentation and licensing terms & conditions. For further informations review the sourcecodes folders.
Compiler
The compiler core.
pp
The preprocessor
macro
The macro system
vm
The virtual machine
lang
Language support, translations of compiler messages to different supported languages
rtl
The runtime library, contains several libraries which can be used to build applications.
rdd
The Replaceable Database Driver Subsystem, contains different database drivers in clipper RDD compatible style.
debug
The Debug system
codepage
Codepages for different languages
common
Common files, shared use by several subsystems