diff --git a/doc/string/aset.rdoc b/doc/string/aset.rdoc
index e06680d16c5435..cac3b67ef580dd 100644
--- a/doc/string/aset.rdoc
+++ b/doc/string/aset.rdoc
@@ -42,7 +42,7 @@ searches for a substring of size +length+ characters (as available)
 beginning at character offset specified by +start+.
 
 If argument +start+ is non-negative,
-the offset is +start':
+the offset is +start+:
 
   s = 'hello'
   s[0, 1] = 'foo'  # => "foo"
diff --git a/tool/sync_default_gems.rb b/tool/sync_default_gems.rb
index c2f352d797ffc8..9d62e954ce11f1 100755
--- a/tool/sync_default_gems.rb
+++ b/tool/sync_default_gems.rb
@@ -194,6 +194,12 @@ def lib((upstream, branch), gemspec_in_subdir: false)
     optparse: lib("ruby/optparse", gemspec_in_subdir: true).tap {
       it.mappings << ["doc/optparse", "doc/optparse"]
     },
+    pathname: repo("ruby/pathname", [
+      ["ext/pathname/pathname.c", "pathname.c"],
+      ["lib/pathname_builtin.rb", "pathname_builtin.rb"],
+      ["lib/pathname.rb", "lib/pathname.rb"],
+      ["test/pathname", "test/pathname"],
+    ]),
     pp: lib("ruby/pp"),
     prettyprint: lib("ruby/prettyprint"),
     prism: repo(["ruby/prism", "main"], [