[nsonha]

I don't get it why would they need to reverse engineer their own software? Was it some sort of RPC without an explicit protocol?

[londons_explore]

I guess they just decided the freerdp codebase (which already runs on Linux) was easier to work with than their codebase (which is deeply integrated into all things windows).

I think the original Microsoft codebase also uses stuff licensed from a third party, so it might have been impossible to opensource.