Ping! is a pretty simple mod. It makes the client play a short sound every time your name is mentioned in chat, kinda like many IRC clients. You can read more about it on the wiki.
Downloads are available on CurseForge
Source code and issue tracking is available on GitHub
Here's a history lesson for you: The mod began as an experimental project in writing some code in the Kotlin language. However, since Forgelin is only available for 1.8+, and I couldn't get a backport working, it was quickly rewritten in Java. Thankfully, Java and Kotlin code is almost identical syntax-wise. There's your history of the mod. You can see how a mod would look like if it were written in Kotlin in the commit history on GitHub.
Downloads are available on CurseForge
Source code and issue tracking is available on GitHub
Here's a history lesson for you: The mod began as an experimental project in writing some code in the Kotlin language. However, since Forgelin is only available for 1.8+, and I couldn't get a backport working, it was quickly rewritten in Java. Thankfully, Java and Kotlin code is almost identical syntax-wise. There's your history of the mod. You can see how a mod would look like if it were written in Kotlin in the commit history on GitHub.