Use codeocean.com/explore, also accessible through the top navigation bar, to browse through published capsules. You can view and run code, as well as make changes. (Your changes will be kept private and won't affect published versions.)
You can revert any modified file back to its original published version by selecting Revert from the Actions menu. You can also revert the entire capsule (code, data, and run environment) back to its published version by selecting Revert from the More Actions (...) menu. Your results will not be affected when you revert your changes.