CSbuild is a powerful dungeon editor developed by Paul R. Stevens, the man who ported Chaos Strikes Back to Windows. This program can read standard dungeons and saved games, but it saves dungeons that can only be read by CSBuild and played with Chaos Strikes Back for Windows and Linux because of an extended file format. This format is required to use some of the unique features that Paul included in the CSBwin engine.
Some of the unique features include:
It can still be usefull if you create dungeons for the original games as it includes a lot of checks to validate that there are no errors in the dungeon.
You will also find the latest available version on Paul Stevens' web site.