org.zkoss.web.classWebResource.cache.etag
From Documentation
Property:
org.zkoss.web.classWebResource.cache.etag
Applicable: globally in zk.xml via <library-property> not as <custom-attribute>
Default: false [Since 5.0.1]
It specifies whether to use ETag to detect and return 304 for matched resource.
If turned on, the cached resource won't be reloaded if the user presses F5 to reload.