As is, the current GNOME is unusable to me without extensions because they refuse to implement support for appindicators. You literally cannot use applications that minimize to tray on vanilla GNOME right now. They have been talking about adding their own protocol for years but that is of no use when things are broken right now.

So what, just use the extension. Currently no cross-desktop API for systrays that doesn’t suck in one or another way exists, so GNOME doesn’t have support for them. If you care that much about not using an extension, implement it for yourself.