In info.magnolia.cms.security.auth.callback.AbstractHttpClientCallback and info.magnolia.cms.util.UrlPatternDelegate we expose possibility to check either URL (url, urlPattern) or original URL (originalUrlPattern, originalUrl). It should be documented what those terms mean in context of those classes.
URL - current request URL, decoded and without the context path
Original URL - original request URL, decoded and without the context path, not modified by any filter

Example (valid for EE as MultisiteFilter is removing first level node name from URL):
Browser request: http://demoauthor.magnolia-cms.com/demo-project/about.html
URL: /about.html - context path and first level node are removed
Original URL: /demo-project/about.html - just context path is removed