Package: mpdecimal Version: 2.5.1-1 mpdecimal was removed from Debian closing bug #1056785, arguing that it is no longer needed for cpython.
However , it is a useful library that may be used directly from C/C++, or through y wrappers for different languages (not only Python!). For instance, I have created a wrapper for D at https://github.com/pdenapo/d_mpdecimal that depends on it, and other wrappers for PyPy, Lua, Php and Elixir are listed in the official page https://www.bytereef.org/mpdecimal/ Note that the latest stable version is 4.0.0, which is newer that the one in buster. Other distributions like Arch include it https://archlinux.org/packages/core/x86_64/mpdecimal/ Pablo De Napoli