Liberator.Resource.last_modified

You're seeing just the callback last_modified, go back to Liberator.Resource module for more information.
Link to this callback

last_modified(arg1)

View Source (since 1.0)

Specs

last_modified(Plug.Conn.t()) :: DateTime.t()

Returns the last modified date of your resource.

This value will be used to respond to caching headers like If-Modified-Since.