§1. External files are written in Inter as their array names: 

typedef struct external_file_compilation_data {
    struct inter_name *exf_iname;
    struct inter_name *IFID_array_iname;
} external_file_compilation_data;

external_file_compilation_data RTExternalFiles::new_data(wording W) {
    external_file_compilation_data efcd;
    package_request *P = Hierarchy::local_package(EXTERNAL_FILES_HAP);
    efcd.exf_iname = Hierarchy::make_iname_with_memo(FILE_HL, P, W);
    efcd.IFID_array_iname = Hierarchy::make_iname_with_memo(IFID_HL, P, W);
    return efcd;
}

void RTExternalFiles::arrays(void) {
    inter_name *iname = Hierarchy::find(NO_EXTERNAL_FILES_HL);
    Emit::named_numeric_constant(iname, (inter_ti) (NUMBER_CREATED(files_data)));
    Hierarchy::make_available(Emit::tree(), iname);

    files_data *exf;
    LOOP_OVER(exf, files_data) {
        if (exf->file_ownership == OWNED_BY_SPECIFIC_PROJECT) {
            packaging_state save =
                Emit::named_string_array_begin(exf->compilation_data.IFID_array_iname, K_value);
            TEMPORARY_TEXT(II)
            WRITE_TO(II, "//%S", exf->IFID_of_owner);
            Emit::array_text_entry(II);
            DISCARD_TEXT(II)
            Emit::array_end(save);
        }
    }

    LOOP_OVER(exf, files_data) {
        packaging_state save = Emit::named_array_begin(exf->compilation_data.exf_iname, K_value);
        Emit::array_iname_entry(Hierarchy::find(AUXF_MAGIC_VALUE_HL));
        Emit::array_iname_entry(Hierarchy::find(AUXF_STATUS_IS_CLOSED_HL));
        if (exf->file_is_binary) Emit::array_numeric_entry(1);
        else Emit::array_numeric_entry(0);
        Emit::array_numeric_entry(0);
        TEMPORARY_TEXT(WW)
        WRITE_TO(WW, "%w", Lexer::word_raw_text(exf->unextended_filename));
        Str::delete_first_character(WW);
        Str::delete_last_character(WW);
        Emit::array_text_entry(WW);
        DISCARD_TEXT(WW)
        switch (exf->file_ownership) {
            case OWNED_BY_THIS_PROJECT: Emit::array_iname_entry(RTBibliographicData::IFID_iname()); break;
            case OWNED_BY_ANOTHER_PROJECT: Emit::array_null_entry(); break;
            case OWNED_BY_SPECIFIC_PROJECT: Emit::array_iname_entry(exf->compilation_data.IFID_array_iname); break;
        }
        Emit::array_end(save);
    }

    iname = Hierarchy::find(TABLEOFEXTERNALFILES_HL);
    packaging_state save = Emit::named_array_begin(iname, K_value);
    Emit::array_numeric_entry(0);
    LOOP_OVER(exf, files_data) Emit::array_iname_entry(exf->compilation_data.exf_iname);
    Emit::array_numeric_entry(0);
    Emit::array_end(save);
    Hierarchy::make_available(Emit::tree(), iname);
}