jQuery is namespace so the function is free for Moo Tools to take hold of.
You are welcome to contribute to MooTools! What we ask of you:
a. To report a bug:
- Create a jsFiddle with the minimal amount of code to reproduce the bug.
- Create a GitHub Issue, and link to the jsFiddle.
b. To fix a bug:
- Clone the repo.
- Add a spec.
- Fix the bug.
- Build and run the specs.
- Push to your GitHub fork.
- Create Pull Request, and send Pull Request.
Obviously including two libraries within the same page is resource-consuming but if it’s acceptable to the project and allows you to implement plugins from each library quickly, this may be a great option for you.