diff --git a/NEWS.md b/NEWS.md
index 24a36475360569..95c02be9513306 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -254,7 +254,7 @@ The following default gems are updated.
 * resolv 0.6.3
 * stringio 3.1.9.dev
 * strscan 3.1.6.dev
-* timeout 0.4.4
+* timeout 0.5.0
 * uri 1.1.1
 * weakref 0.1.4
 * zlib 3.2.2
diff --git a/ext/-test-/time/leap_second.c b/ext/-test-/time/leap_second.c
deleted file mode 100644
index ee7011fa97e983..00000000000000
--- a/ext/-test-/time/leap_second.c
+++ /dev/null
@@ -1,15 +0,0 @@
-#include "ruby.h"
-#include "internal/time.h"
-
-static VALUE
-bug_time_s_reset_leap_second_info(VALUE klass)
-{
-    ruby_reset_leap_second_info();
-    return Qnil;
-}
-
-void
-Init_time_leap_second(VALUE klass)
-{
-    rb_define_singleton_method(klass, "reset_leap_second_info", bug_time_s_reset_leap_second_info, 0);
-}
diff --git a/include/ruby/backward.h b/include/ruby/backward.h
index f804c2c36e9425..3a0fda9ec56dda 100644
--- a/include/ruby/backward.h
+++ b/include/ruby/backward.h
@@ -11,10 +11,6 @@
 #include "ruby/internal/interpreter.h"
 #include "ruby/backward/2/attributes.h"
 
-#define RBIMPL_ATTR_DEPRECATED_SINCE(ver) RBIMPL_ATTR_DEPRECATED(("since " #ver))
-#define RBIMPL_ATTR_DEPRECATED_INTERNAL(ver) RBIMPL_ATTR_DEPRECATED(("since "#ver", also internal"))
-#define RBIMPL_ATTR_DEPRECATED_INTERNAL_ONLY() RBIMPL_ATTR_DEPRECATED(("only for internal use"))
-
 RBIMPL_ATTR_DEPRECATED_INTERNAL_ONLY() void rb_clear_constant_cache(void);
 
 /* from version.c */
diff --git a/include/ruby/internal/attr/deprecated.h b/include/ruby/internal/attr/deprecated.h
index e1bbdbd15ad0de..9c9dea1df2794a 100644
--- a/include/ruby/internal/attr/deprecated.h
+++ b/include/ruby/internal/attr/deprecated.h
@@ -72,4 +72,11 @@
 # define RBIMPL_ATTR_DEPRECATED_EXT(msg) RBIMPL_ATTR_DEPRECATED(msg)
 #endif
 
+#define RBIMPL_ATTR_DEPRECATED_SINCE(ver) \
+    RBIMPL_ATTR_DEPRECATED(("since " #ver))
+#define RBIMPL_ATTR_DEPRECATED_INTERNAL(ver) \
+    RBIMPL_ATTR_DEPRECATED(("since "#ver", also internal"))
+#define RBIMPL_ATTR_DEPRECATED_INTERNAL_ONLY() \
+    RBIMPL_ATTR_DEPRECATED(("only for internal use"))
+
 #endif /* RBIMPL_ATTR_DEPRECATED_H */
diff --git a/include/ruby/internal/intern/vm.h b/include/ruby/internal/intern/vm.h
index 779f77fe91fcb5..0d25a9cdb041fc 100644
--- a/include/ruby/internal/intern/vm.h
+++ b/include/ruby/internal/intern/vm.h
@@ -95,7 +95,6 @@ VALUE rb_check_funcall(VALUE recv, ID mid, int argc, const VALUE *argv);
  */
 VALUE rb_check_funcall_kw(VALUE recv, ID mid, int argc, const VALUE *argv, int kw_splat);
 
-#ifdef RBIMPL_ATTR_DEPRECATED_INTERNAL
 /**
  * This API  is practically a  variant of rb_proc_call_kw()  now.  Historically
  * when there  still was a  concept called `$SAFE`, this  was an API  for that.
@@ -112,7 +111,6 @@ VALUE rb_check_funcall_kw(VALUE recv, ID mid, int argc, const VALUE *argv, int k
  */
 RBIMPL_ATTR_DEPRECATED_INTERNAL(4.0)
 VALUE rb_eval_cmd_kw(VALUE cmd, VALUE arg, int kw_splat);
-#endif
 
 /**
  * Identical to rb_funcallv(), except it takes Ruby's array instead of C's.
diff --git a/internal/time.h b/internal/time.h
index e21b3574f6db7a..1f3505f5bc7685 100644
--- a/internal/time.h
+++ b/internal/time.h
@@ -27,11 +27,8 @@ struct timeval rb_time_timeval(VALUE);
 
 RUBY_SYMBOL_EXPORT_BEGIN
 /* time.c (export) */
-void ruby_reset_leap_second_info(void);
-#ifdef RBIMPL_ATTR_DEPRECATED_INTERNAL_ONLY
-RBIMPL_ATTR_DEPRECATED_INTERNAL_ONLY()
-#endif
-void ruby_reset_timezone(const char *);
 RUBY_SYMBOL_EXPORT_END
 
+void ruby_reset_timezone(const char *);
+
 #endif /* INTERNAL_TIME_H */
diff --git a/lib/timeout.rb b/lib/timeout.rb
index 36cd0f915bc7ff..1640542d6f806a 100644
--- a/lib/timeout.rb
+++ b/lib/timeout.rb
@@ -20,7 +20,7 @@
 
 module Timeout
   # The version
-  VERSION = "0.4.4"
+  VERSION = "0.5.0"
 
   # Internal error raised to when a timeout is triggered.
   class ExitException < Exception
diff --git a/test/ruby/test_time_tz.rb b/test/ruby/test_time_tz.rb
index f66cd9bec2eedc..473c3cabcb4d50 100644
--- a/test/ruby/test_time_tz.rb
+++ b/test/ruby/test_time_tz.rb
@@ -1,6 +1,5 @@
 # frozen_string_literal: false
 require 'test/unit'
-require '-test-/time'
 
 class TestTimeTZ < Test::Unit::TestCase
   has_right_tz = true
diff --git a/time.c b/time.c
index 2a121d5fcc8f74..b2eed2daf3b85c 100644
--- a/time.c
+++ b/time.c
@@ -746,6 +746,8 @@ get_tzname(int dst)
 }
 #endif
 
+static void ruby_reset_leap_second_info(void);
+
 void
 ruby_reset_timezone(const char *val)
 {