[qppo]

> Companies do C/C++ linking to Electron itself in a web app?

That's one of the selling points of Electron, write your frontend in whatever JS framework your frontend devs want to use, provide hooks through node modules to your application where the heavy lifting is done using whatever language/runtime you want.

> Do they also do C/C++ linking to the browser for the web app version fo the app?

If a web version can exists (Electron apps cover spaces that web apps can't), and it's identical to your Electron app, then your Electron app never needed to be written in the first place.