There're only these unsupported and outdated plugins:
https://elgg.org/plugins/2085423
https://elgg.org/plugins/1205095
https://elgg.org/plugins/1198657
https://elgg.org/plugins/1190435
In Elgg v5 a site administrator can configure theme variables like colors on the backend (Configure -> Theme). There are also options to upload a favicon or change the site name. This however does not allow a site admin to change layout of the site. To do that you probably need a (custom) theme.
info@elgg.org
Security issues should be reported to security@elgg.org!
©2014 the Elgg Foundation
Elgg is a registered trademark of Thematic Networks.
Cover image by RaĆ¼l Utrera is used under Creative Commons license.
Icons by Flaticon and FontAwesome.