Users can switch themes in this panel, where do I need to set it in the backend?

[david (David Taylor)]

To allow users to change themes via the hamburger menu, you need to install and enable this component:

Hamburger Theme Selector

This theme component is end-of-life and is no longer supported This theme component no longer works in recent versions of Discourse. Please see Sidebar Theme Toggle as an alternative. Summary Hamburger Theme Selector adds a theme selector in the hamburger menu provided there is more than 1 user selectable theme. This selector works with both logged-on users and anonymous users. Repository Link https://github.com/discourse/discourse-ham…