Under automation read roots, a reply replaced only the path inside a
`file:///outside/a.svg` URL, which left `file://a.svg`, a URL that names a
host. The whole URL of an absolute path, with `localhost`, another host or
no host, is now replaced with the file name, unless part of its scheme was
already replaced. A reply key rewritten to read the same as another key of
its object took that key's place and its field was lost; the rewritten key
now takes ` (2)`, ` (3)` and so on, and a key that is not rewritten keeps
its name.