.DCU (Delphi Compiled Unit) files are binary files that are used between compiling source (text) and linking the executable. They're created by the compiler, joined together in memory, combined with the startup code and put into an actual executable (.EXE/.DLL/.BPL) by the linker

- added header with link to official documentation about Delphi filetypes
- added some missed file extensions
- made some grouping with descriptions

*.~*~ not match backup files