Downloading Mdate 1.5.7 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. The program lies within Productivity Tools, more precisely Timekeeping. We recommend checking the downloaded files with any free antivirus. The actual developer of this free software for Mac is Sean Dwyer.
From the developer:
Mdate is a utility that converts Gregorian dates to Mayan Long Count dates. It was originally an implementation of some algorithms published by N. Dershowitz and E.M. Reingold in their book Calendrical Calculations, but is now a GPL project and uses some code derived from other GPL sources.
You may want to check out more Mac applications, such as VTCLab Media Analyzer, which might be related to Mdate.