diff --git a/control/README.md b/control/README.md
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+This code is responsible for the local command bus used to control the ZeroTier One service on a local machine via zerotier-cli or the Qt GUI. It's not part of the core node implementation. It uses Unix domain sockets on unix-like OSes and named pipes on Windows. Authentication is via a simple token mechanism. (Eventually this part of the software is getting a rework.)
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diff --git a/ext/README.md b/ext/README.md
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+The ext/ folder contains third party code, drivers, installation support files, etc.
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-ext/ contains external code, such as libraries, and scripts for building such.
diff --git a/windows/README.md b/windows/README.md
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+This folder contains the Windows driver code, Windows-specific service code, and the Microsoft Visual Studio projects and "solution" for doing Windows builds.
+
+This code may also build with MinGW but this hasn't been tested.