Public collection links
A public collection is a collection of assets that are publicly available through the media delivery service. Collections are configured in the Sitecore Content Hub instance but are served by the media delivery service (MDS). This means the collection is shared with a public link and each asset contained in the public collection is served by the MDS through a delivery link.
Themes
Public collections use the theme provided by the Content Hub instance so users experience the same look and feel on the new application as on the Content Hub instance.
The web application fetches information about the theme from Content Hub and caches it until notified to refresh it. When you start the application for the first time, the Content Hub portal must be running, or the new application won't find the relevant CSS. Otherwise, the application retrieves the latest theme configuration from an ini file.
The CSS comes from Content Hub directly or from a CDN.
If a superuser changes or modifies the current default theme, the change is automatically applied to the new web application.
You can clear the cache using the admin API. This can be useful if you do not want to wait for the cache to expire before seeing your applied changes. To clear the cache, send an HTTP POST request to <BASE_PUBLIC_COLLECTIONS_ADDRESS>/api/media-delivery/admin/v1/<TENANTID>.