diff --git a/bin/README.md b/bin/README.md
index 7b09f9c8b..b918e169d 100644
--- a/bin/README.md
+++ b/bin/README.md
@@ -1 +1,9 @@
-Developer binaries built with the makefile go here.
+Interesting/historical binaries are kept here, such as:
+
+- Optimised cabal builds, copied here from cabal's bin directory.
+- Old versions, with the -X.Y suffix. Used for performance benchmarking.
+- Builds for other platforms, with a -PLATFORM-ARCH suffix, maybe compressed for download.
+- Non-optimised developer builds compiled with make (*dev).
+  Used during development for quicker, multi-package, and on-change compilation.
+- cabal and/or make builds with profiling enabled (*-prof).
+  Used for investigating time and space usage.