This mapping allows to serve content

• either mgnl:renderable (pretty much nothing except mgnl:page these days, used to be mgnl:resource)
• jcr:data nodes (only contacts/personas in demo bundle)

from different workspaces.

The default configuration involves these mappings:

• personas allows to render photos via rendering filter but instead (as the direct upload field is deprecated), it could just simply link to assets
• the same applies for photos in contacts
• tours is used just internally for virtualURIMapping so the rendering filter is not even used
• /resources/ links were replaced by /.resources/ since Magnolia 5.4 (MGNLRES-144)
• /dam/ links were replaced by /.dam/ since Magnolia 5.0 (MGNLDAM-82)

Relevant documentation:
https://docs.magnolia-cms.com/product-docs/6.2/Administration/URI-mapping/URI-to-repository-mapping.html
https://docs.magnolia-cms.com/product-docs/6.2/Administration/Architecture/Request-processing-and-filters/Filters.html#_repository_mapping
https://docs.magnolia-cms.com/product-docs/6.2/Features/Search/Jackrabbit-search.html#_configuring_uri2repository_mapping

Uri2Repository mapping can be still relevant in multisite context.

Configuration in the site definition overrides the configuration in /server/URI2RepositoryMapping/mappings/<workspace>, resulting in site-specific definitions.