diff --git a/sig/base64.rbs b/sig/base64.rbs
index 147e874..ee6783f 100644
--- a/sig/base64.rbs
+++ b/sig/base64.rbs
@@ -139,8 +139,9 @@
 #     Base64.strict_decode64("MDEyMzQ1Njc=")  # => "01234567"
 #     Base64.strict_decode64("MDEyMzQ1Njc==") # Raises ArgumentError
 #
-# Method Base64.urlsafe_decode64 allows padding in `str`, which if present, must
-# be correct: see [Padding](Base64.html#module-Base64-label-Padding), above:
+# Method Base64.urlsafe_decode64 allows padding in the encoded string, which if
+# present, must be correct: see
+# [Padding](Base64.html#module-Base64-label-Padding), above:
 #
 #     Base64.urlsafe_decode64("MDEyMzQ1Njc") # => "01234567"
 #     Base64.urlsafe_decode64("MDEyMzQ1Njc=") # => "01234567"
@@ -182,21 +183,21 @@
 module Base64
   # <!--
   #   rdoc-file=lib/base64.rb
-  #   - decode64(str)
+  #   - Base64.decode(encoded_string) -> decoded_string
   # -->
   # Returns a string containing the decoding of an RFC-2045-compliant
-  # Base64-encoded string `str`:
+  # Base64-encoded string `encoded_string`:
   #
   #     s = "VGhpcyBpcyBsaW5lIDEKVGhpcyBpcyBsaW5lIDIK\n"
   #     Base64.decode64(s) # => "This is line 1\nThis is line 2\n"
   #
-  # Non-Base64 characters in `str` are ignored; see [Encoding Character
+  # Non-Base64 characters in `encoded_string` are ignored; see [Encoding Character
   # Set](Base64.html#module-Base64-label-Encoding+Character+Sets) above: these
   # include newline characters and characters `-` and `/`:
   #
   #     Base64.decode64("\x00\n-_") # => ""
   #
-  # Padding in `str` (even if incorrect) is ignored:
+  # Padding in `encoded_string` (even if incorrect) is ignored:
   #
   #     Base64.decode64("MDEyMzQ1Njc")   # => "01234567"
   #     Base64.decode64("MDEyMzQ1Njc=")  # => "01234567"
@@ -206,9 +207,10 @@ module Base64
 
   # <!--
   #   rdoc-file=lib/base64.rb
-  #   - encode64(bin)
+  #   - Base64.encode64(string) -> encoded_string
   # -->
-  # Returns a string containing the RFC-2045-compliant Base64-encoding of `bin`.
+  # Returns a string containing the RFC-2045-compliant Base64-encoding of
+  # `string`.
   #
   # Per RFC 2045, the returned string may contain the URL-unsafe characters `+` or
   # `/`; see [Encoding Character
@@ -241,23 +243,23 @@ module Base64
 
   # <!--
   #   rdoc-file=lib/base64.rb
-  #   - strict_decode64(str)
+  #   - Base64.strict_decode64(encoded_string) -> decoded_string
   # -->
   # Returns a string containing the decoding of an RFC-2045-compliant
-  # Base64-encoded string `str`:
+  # Base64-encoded string `encoded_string`:
   #
   #     s = "VGhpcyBpcyBsaW5lIDEKVGhpcyBpcyBsaW5lIDIK"
   #     Base64.strict_decode64(s) # => "This is line 1\nThis is line 2\n"
   #
-  # Non-Base64 characters in `str` not allowed; see [Encoding Character
-  # Set](Base64.html#module-Base64-label-Encoding+Character+Sets) above: these
-  # include newline characters and characters `-` and `/`:
+  # Non-Base64 characters in `encoded_string` are not allowed; see [Encoding
+  # Character Set](Base64.html#module-Base64-label-Encoding+Character+Sets) above:
+  # these include newline characters and characters `-` and `/`:
   #
   #     Base64.strict_decode64("\n") # Raises ArgumentError
   #     Base64.strict_decode64('-')  # Raises ArgumentError
   #     Base64.strict_decode64('_')  # Raises ArgumentError
   #
-  # Padding in `str`, if present, must be correct:
+  # Padding in `encoded_string`, if present, must be correct:
   #
   #     Base64.strict_decode64("MDEyMzQ1Njc")   # Raises ArgumentError
   #     Base64.strict_decode64("MDEyMzQ1Njc=")  # => "01234567"
@@ -267,9 +269,10 @@ module Base64
 
   # <!--
   #   rdoc-file=lib/base64.rb
-  #   - strict_encode64(bin)
+  #   - Base64.strict_encode64(string) -> encoded_string
   # -->
-  # Returns a string containing the RFC-2045-compliant Base64-encoding of `bin`.
+  # Returns a string containing the RFC-2045-compliant Base64-encoding of
+  # `string`.
   #
   # Per RFC 2045, the returned string may contain the URL-unsafe characters `+` or
   # `/`; see [Encoding Character
@@ -301,18 +304,19 @@ module Base64
 
   # <!--
   #   rdoc-file=lib/base64.rb
-  #   - urlsafe_decode64(str)
+  #   - Base64.urlsafe_decode64(encoded_string) -> decoded_string
   # -->
-  # Returns the decoding of an RFC-4648-compliant Base64-encoded string `str`:
+  # Returns the decoding of an RFC-4648-compliant Base64-encoded string
+  # `encoded_string`:
   #
-  # `str` may not contain non-Base64 characters; see [Encoding Character
-  # Set](Base64.html#module-Base64-label-Encoding+Character+Sets) above:
+  # `encoded_string` may not contain non-Base64 characters; see [Encoding
+  # Character Set](Base64.html#module-Base64-label-Encoding+Character+Sets) above:
   #
   #     Base64.urlsafe_decode64('+')  # Raises ArgumentError.
   #     Base64.urlsafe_decode64('/')  # Raises ArgumentError.
   #     Base64.urlsafe_decode64("\n") # Raises ArgumentError.
   #
-  # Padding in `str`, if present, must be correct: see
+  # Padding in `encoded_string`, if present, must be correct: see
   # [Padding](Base64.html#module-Base64-label-Padding), above:
   #
   #     Base64.urlsafe_decode64("MDEyMzQ1Njc") # => "01234567"
@@ -323,9 +327,9 @@ module Base64
 
   # <!--
   #   rdoc-file=lib/base64.rb
-  #   - urlsafe_encode64(bin, padding: true)
+  #   - Base64.urlsafe_encode64(string) -> encoded_string
   # -->
-  # Returns the RFC-4648-compliant Base64-encoding of `bin`.
+  # Returns the RFC-4648-compliant Base64-encoding of `string`.
   #
   # Per RFC 4648, the returned string will not contain the URL-unsafe characters
   # `+` or `/`, but instead may contain the URL-safe characters `-` and `_`; see