open_source(+File, -Stream) is semidet[multifile, library(prolog_clause)]
Hook into clause_info/5 that opens the stream holding the source for a specific clause. Thus, the query must succeed. The default implementation calls open/3 on the File property.
clause_property(ClauseRef, file(File)),
prolog_clause:open_source(File, Stream)
 prolog_clause:open_source(+File, -Stream) is semidet[multifile, wordlist(trace)]
Open SWISH non-file sources.