diff --git a/README.md b/README.md
index ac8051b..9b37971 100644
--- a/README.md
+++ b/README.md
@@ -4,6 +4,8 @@ A container that makes the RTEMS powerpc beatnik Board Support Package (BSP).
 
 This container gets the sources from RTEMS releases, builds the toolchain and then compiles the BSP.
 
+The developer target serves as an archive for the source code. The runtime target is a minmal container with the RTEMS powerpc-beatnik BSP only, intended to be used as a base for epics-base builds.
+
 The current configuration is:-
 - rtems version: 6.1-rc2
 - patches for MVME5500 boards used at DLS