[ `About of abouts (* current proof *)
| `Check of string (* term *)
| `Cic of Cic.term * Cic.metasenv
+ | `NCic of NCic.term * NCic.context * NCic.metasenv * NCic.substitution
| `Dir of string (* "directory" in cic uris namespace *)
| `HBugs of [ `Tutors ] (* list of available HBugs tutors *)
| `Metadata of [ `Deps of [`Fwd | `Back] * UriManager.uri ]
| `About `Grammar -> "about:grammar"
| `Check _ -> "check:"
| `Cic (_, _) -> "term:"
+ | `NCic (_, _, _, _) -> "nterm:"
| `Dir uri -> uri
| `HBugs `Tutors -> "hbugs:/tutors/"
| `Metadata meta ->