The jar: URI scheme can be used to access ZIP archives. (I don't know if this program already implements it or not, although Firefox does implement it, and I use it a lot in Firefox.) The format is jar:URL!/PATH where URL is the URL of the ZIP archive file (usually a local file, so it starts with file:///), and PATH is the path of the file within the ZIP archive. If it is the name of a directory or if the path is omitted (so that it ends with !/) then it will display a directory listing. Relative URLs starting with / are relative to the root of the ZIP archive.

One use of this is to display EPUB and Gempub files, although it can be used with any ZIP archive file.