Nope.
I have absolutely no idea what it is.
I even went Googling and just ended up at a page saying:
"Open Source MANO (OSM) is the open source community that aims to deliver a production-quality MANO stack for NFV, capable of consuming openly published information models, available to everyone, suitable for all VNFs, operationally significant and VIM-independent. OSM is aligned to NFV ISG information models while providing first-hand feedback based on its implementation experience."
Now, I'm not afraid of a TLA but would someone like to put in a sentence explaining what this thing actually is?