This project is about integration with the Gnome desktop. It uses xfreerdp RemoteApp support[1] under the hood (an up to date equivalent of seamlessrdp).
"SeamlessRDP requires Windows Server 2008r2 or later to operate correctly."
That seems like a very limiting requirement for many use-cases.
How is this more limiting than WinApps which only supports Windows 10 with RDP?
Windows 10 with RDP is cheaper and has a significantly larger usebase?
Since Windows 10 is newer than Windows Server 2008 I assume it is supported as well, since it says "Windows Server 2008 or later" is required.
I would not, server is a different product line and MS has different features of RDP enabled for different versions. Typically you distinguish consumer and server versions when listing compatible versions.
And RemoteApp is not officially supported (as a server) on Windows 10 Pro/Home.