I collect a lot of stuff on my Mac. I don't even know what this hummer is for?

Do I need it? May I delete it and not cause any ill effects on my iMac 24 inch.

From XQuartz :

The Xquartz project is an open-source effort to develop a version of the X.org X Window System that runs on Mac OS X. Together with supporting libraries and applications, it forms the X11.app that Apple has shipped with OS X since version 10.5.

The updates available on this site are not official Apple releases. They are a convenient way for users to stay up to date with progress made in the open source community (in which Apple is participating). Official Apple releases will come from Apple (most likely through OS and Security Updates via Software Update). These updates will likely incorporate many of the changes made in our releases when and if Apple deems them appropriate.

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