For people interested in reverse engineering stuff with Borland C++ or Borland C++ Builder, I have collected a variety of versions (including some I dumped myself after acquiring them on eBay):
Borland C++
2.0: WinWorldPC
3.0, 3.1: WinWorldPC
4.0, 4.5, 4.52: WinWorldPC
4.01, 4.02, 4.51, 4.53: probably lost to history
5.0: Internet Archive
5.01: probably lost to history
5.02: WinWorldPC
Borland C++ Builder
1.0: Internet Archive
4: currently waiting for a physical copy...
5: WinWorldPC
6: WinWorldPC
I have dumped the installation directory from every version starting with BCPP 4.0 into a GitHub repository that allows following through the histories of the include files and the RTL source.
Note that the Borland sources are not complete - they only started shipping the RTTI and exception handler source code with C++ Builder 5 (or possibly Builder 4, no way to know until I get my hands on it).