What is Chromium?
Chromium is something you're likely using right now without even realizing it. Are you using Arc Browser, Chrome, Brave, or even Microsoft Edge right now? Okay, then you're using Chromium.
You know those extensions you have in the top-right corner? Yep, those are Chromium extensions (often referred to as "Chrome Extensions"). Little do people know, Google built an open-source foundation to the browser, for which most of the top browsers on the market use as their foundation.
Competition
I mean you're not exactly looking at traditional competition here, but Apple does use a competing standard called Webkit. So if you're using Safari on your computer, that's running on Webkit instead of Chromium.
The super interesting part here though is if you're using iOS, any browser you're using is actually built atop Webkit—even Google Chrome. Apple requires Webkit be used on iOS regardless.
Why exactly? Well, Google pays Apple some $20bn per year to be the default search engine in Safari, so holding onto Webkit on iOS and iPad is probably one of their leverage points:
“At-least we still own the foundation of the browser for our products!”
-Apple (probably) 🤷
Final Verdict
This genuinely probably doesn't mean much to you, but you're probably using Chromium and you probably don't care.
Just know that it makes for switching between Chromium-based browsers far easier—from transferring bookmarks, to extensions, and everything inbetween.