It is about time OpenSSH takes the submitted patch (5 years in waiting!) into a release so that users can start composing their ~/.ssh/config from multiple files. With the advent of cloud computing, many users have a need for including generated parts into their configuration which would be considerably easier with an Include option. And even better would be if it would support config directories like "~/.ssh/config.d/*" which would include all files matching the given pattern.

Even better would be an EndMatch block.