1. Shared libraries for blt This is the shared libraries for BLT. You should only need this if you are using programs which are linked to blt, or are developing programs in BLT. BLT is an extension to the Tk toolkit, adding new widgets, geometry managers, and miscellaneous commands. It does not require any patching of the Tcl or Tk source files. An attempt is being made to unify the BLT libraries so that the package is independent of whatever tcl/tk library (e.g. 8.0,8.2,8.3) you are using. This will be via the tcl stubs interface. As part of this process, blt8.0 is obsolete and this package dynamically chooses the correct version of BLT library to match your situation. This makes is a lot bigger than if you choose the library versions yourself, but means that you always have the version you need (not always the case under the old system) From Debian 3.0r0 APT