Initiator of subordinating adverbial relative clause with leftwards logical scope. The adverbial clause binds the resumptive pronoun {ke'a} to the outer clause, which becomes irrealis (i.e. not necessarily claimed to be true). Terminator: {se'u}.
This cmavo is synonymous to the so-called "new-soi", described at https://mw.lojban.org/papri/new_soi