Package Directive
The package
directive introduces a package source
file. A package is a special kind of DLL that contains units that can
be linked dynamically into another
project.
A package source file has the extension .dpk (for Delphi package). A single file contains a single package declaration.
You can edit the package source file by hand, but usually you will use the Package Manager in Delphi’s IDE.
If you edit the package source file manually, make sure the syntax is correct. Delphi’s compiler is not always graceful when it encounters syntax errors in a package source file.