Maintenance is mainly focused on stability, safety and performance. What is not included, among other things, are changes to the content of the website, including text, images, pages, menus, etc, additions of new functionality to the website or changes to existing functionality (further developments and feature requests), changes to the design of the website, installation of new WordPress plugins, installation of a new WordPress theme, hosting, server or email related issues and SEO / Search Engine optimizations.
I offer a separately service for this type of jobs.