Chrome extensions can be installed in many ways. Does a chrome extension need to be sourced from the chrome web store in order to be considered an chrome extens

Chrome extensions can be installed in many ways. Does a chrome extension need to be sourced from the chrome web store in order to be considered an chrome extension? One method to install an extension is the chrome web store.. the other methods are typically only used by developers (hence all the dev mode comments) and malware (hence all the "I can live with this" comments)