If you want to run the very latest version of Meshroom or some custom developer version, you need to get the sources.
Meshroom is a Python application and it relies on the AliceVision framework.
The following versions of python are required:
Windows: Python 3 (>=3.5)
Linux / Mac OS X: Python 3 (>=3.5) or Python 2 (>= 2.7)
No Python 2.7 support on Windows?
Official Python 2.7 binary package is built with Visual Studio 2008, while PySide2/Qt is built using Visual Studio 2015/2017. Therefore, in order to avoid mixing MSVC runtime libraries, Qt does not ship PySide2 wheels for Python 2.7 on Windows (as explained here). Note that for using Meshroom in command line mode only (no UI), PySide2 is not required and Python 2.7 would be fine.