Delphi Form Files (.dfm) are stored as normal Windows binary
resources (rcData) in your executable. Examples of other resources
in an .exe: bitmaps, cursors, icons, and strings.
You can use a utility such as Resource Workshop, or the Resource
Explorer demo application which comes with D3 (demos\resxplor),
to extract any resource from an .exe into a separate file. This means
you could easily extract a .dfm resource from the .exe into a separate
file.
You can also use the Delphi TResourceStream class to access
resource data as a stream, and you can easily copy a resource stream
to another stream, such as a file stream or memory stream.
Once you have extracted the .dfm from the .exe, you can use .dfm
utility procedures such as ObjectBinaryToText, ObjectTextToBinary,
ReadComponentResFile, WriteComponentResFile,
TStream.ReadComponent, TStream.WriteComponent, etc., to
manipulate the .DFM.