The following URLs are specified relative to base Trac URL:

 /chrome :: for any kind of ''static resources'' (usually ''images'', ''.css'' and ''.js''). They are called ''static'', because they don't require any server-side processing and can be served as-is. In fact to avoid firing [TracDev/RequestHandling Trac request handling] many people prefer to have those static resources  [TracInstall#MappingStaticResources served directly by the web server].
 /chrome/site :: using this URL Trac accesses static resources for TracInterfaceCustomization that were uploaded to [TracEnvironment environment's] ''htdocs/'' directory 
 /chrome/shared :: using this URL Trac accesses static resources in a shared location defined by the `htdocs_dir` option in the `inherit` section of the TracIni.
 /chrome/common :: with this URL Trac accesses static resources used by default Trac scheme - these are usually found in ''htdocs/'' subdirectory in Trac installation location
 /chrome/<pluginname> :: plugins may also have static resources that can be accessed using Trac chrome handler

All static resources can be exported with '''trac-admin deploy''' command to serve them independently. The process is described in detail in TracInstall#MappingStaticResources. Just do not forget to re-export them after installing new plugins or upgrading Trac.