We recommend checking the downloaded files with any free antivirus. The program lies within Developer Tools, more precisely General.
From the developer:
Rudix is a world class collection of pre-compiled and ready to use UNIX compatible software which are not available from a fresh installation of Mac OS X but are popular among other UNIX environments (Linux and BSDs). Here you can find 44 items: utilities, programming languages, libraries and tools delivered as standard Mac OS X packages.