diff --git a/collects/redex/examples/r6rs/README b/collects/redex/examples/r6rs/README
index 3f7d63a0c8..1e46c92fed 100644
--- a/collects/redex/examples/r6rs/README
+++ b/collects/redex/examples/r6rs/README
@@ -2,24 +2,24 @@ This directory a the PLT Redex implementation of the
 R6RS operational semantics and a test suite for the
 semantics.
 
-== r6rs.ss: the semantics itself.
+== r6rs.rkt: the semantics itself.
 
-== r6rs-tests.ss: the test suite for the semantics. Use:
+== r6rs-tests.rkt: the test suite for the semantics. Use:
 
-   racket -t r6rs-tests.ss -m
+   racket -t r6rs-tests.rkt -m
 
    to run the tests and see a single period shown per test
    run (each test that explores more than 100 states shows a
    colon for each 100 states it explores). To see a more
    verbose output (that shows each test), use:
 
-   racket -t r6rs-tests.ss -m #t
+   racket -t r6rs-tests.rkt -m #t
 
-== show-examples.ss: use this file to explore particular
+== show-examples.rkt: use this file to explore particular
    examples in a GUI. Its content shows how to use it and
    gives a few examples. Either run it in DrRacket's module
    language, or like this from the commandline:
 
-   gracket show-examples.ss
+   gracket show-examples.rkt
 
-== test.ss: test suite infrastructure
+== test.rkt: test suite infrastructure