Exactly reversed! Chromium is an open-source browser for Windows, Linux, macOS and Android, which is not intended for end users, but only for developers. There is no installer, only the source code and semi-official builds.
Chromium is mostly made of Chromium (with the exception of the iOS version), but it adds some of its components - in particular an auto-updater, audio and video codecs, plugins for Flash and DRM protected content, and Google logos , Chrome itself is not open source.
Chromium was started in 2008 by Google, whose employees still contribute most of the code and control the project. But not everything comes from Google: So far, almost 50 companies and 1000 individual developers were involved. Among the most notable contributors are Opera, Vivaldi, Yandex, BlackBerry, Facebook, Spotify, Akamai, ARM, HP, IBM, LG, Nvidia - and even Mozilla. Of the individually listed developers many Samsung, Amazon and Intel can be assigned.