console.log doesn't print all session properties in node js

This code

router.post("/", (req, res) =>
{
    console.log(req.session)
    console.log(req.session.id)
})

prints

Session { cookie: { path: '/', _expires: null, originalMaxAge: null, httpOnly: true }, passport: { user: 'red' } }

and then

2sJgQxjBCbKgPiUN3pUdcDty_35GELeE

Is session.id stored inside session? Why it is not displayed after the first call to console.log?

Here is the setup:

var RedisStore = connectRedis(session)
app.use(session(
    {
        store: new RedisStore({ url: config.redisStore.url }),
        secret: config.redisStore.url,
        resave: false,
        saveUninitialized: false
    }))

via user2136963