diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
index 29da2850..bb5e8d39 100644
--- a/.github/pull_request_template.md
+++ b/.github/pull_request_template.md
@@ -2,7 +2,7 @@ If you are patching a security vulnerability, please do not submit a pull
 request. Instead, follow the guidelines described in our
 [security policy](../blob/main/SECURITY.md).
 
-If you are submitting a bug fix for an an error or fixing an incompatibility
+If you are submitting a bug fix for an error or fixing an incompatibility
 with the [official JSON5 specification][spec], please continue.
 
 If you are submitting a feature request or code improvement that is compatible
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5d04cf06..5756a4c1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -322,7 +322,7 @@ This release tightens JSON5 support and adds helpful utility features:
 This was the first implementation of this JSON5 parser.
 
 - Support unquoted object keys, including reserved words. Unicode characters
-  and escape sequences sequences aren't yet supported.
+  and escape sequences aren't yet supported.
 
 - Support single-quoted strings.
 
diff --git a/README.md b/README.md
index 00ee7939..89524bc7 100644
--- a/README.md
+++ b/README.md
@@ -20,12 +20,12 @@ and has been adopted by major projects like
 [WebStorm](https://www.jetbrains.com/help/webstorm/json.html),
 and [more](https://github.com/json5/json5/wiki/In-the-Wild)**.
 It's also natively supported on **[Apple platforms](https://developer.apple.com/documentation/foundation/jsondecoder/3766916-allowsjson5)**
-like **MacOS** and **iOS**.
+like **macOS** and **iOS**.
 
 Formally, the **[JSON5 Data Interchange Format](https://spec.json5.org/)** is a superset of JSON
 (so valid JSON files will always be valid JSON5 files)
 that expands its syntax to include some productions from [ECMAScript 5.1] (ES5).
-It's also a strict _subset_ of ES5, so valid JSON5 files will always be valid ES5.
+It's also a _subset_ of ES5, so valid JSON5 files will always be valid ES5.[*](#ecmascript-compatibility)
 
 This JavaScript library is a reference implementation for JSON5 parsing and serialization,
 and is directly used in many of the popular projects mentioned above
@@ -239,7 +239,7 @@ please submit an issue to the official
 **[_specification_ repository](https://github.com/json5/json5-spec)**.
 
 Note that we will never add any features that make JSON5 incompatible with ES5;
-that compatibility is a fundamental premise of JSON5.
+that compatibility is a fundamental premise of JSON5.[*](#ecmascript-compatibility)
 
 To report bugs or request features regarding this **JavaScript implementation**
 of JSON5, please submit an issue to **_this_ repository**.
@@ -248,6 +248,14 @@ of JSON5, please submit an issue to **_this_ repository**.
 To report a security vulnerability, please follow the follow the guidelines
 described in our [security policy](./SECURITY.md).
 
+## ECMAScript Compatibility
+While JSON5 aims to be fully compatible with ES5, there is one exception where
+both JSON and JSON5 are not. Both JSON and JSON5 allow unescaped line and
+paragraph separator characters (U+2028 and U+2029) in strings, however ES5 does
+not. A [proposal](https://github.com/tc39/proposal-json-superset) to allow these
+characters in strings was adopted into ES2019, making JSON and JSON5 fully
+compatible with ES2019.
+
 ## License
 MIT. See [LICENSE.md](./LICENSE.md) for details.