Inside the Extensions folder went the individual extensions, bits of add-on code which extended (hence the name extensions) the capabilities of the Macintosh. Extensions also work fine when they are on the root level of the System Folder itself (as was the case back in System 6 and even earlier versions of the Macintosh system software). Should an extension be disabled, and should an Extensions (Disabled) folder be present, the extension-in-question is, instead, moved to that folder.