As you hopefully know, Lightning Web Components (LWC’s) were introduced in 2019. Right away, Don Robins met with Salesforce expert, Chuck Liddell and they produced a free Pluralsight course, titled, “Play by Play: Understanding Lightning Web Components for Salesforce Developers“.
In that course, Chuck walked everyone through the Open Source Recipes Repo that Salesforce provided when it first released LWC’s. I remember in one part of that excellent course, that Chuck mentioned that we could not see the source code for any of the base Lightning components. Specifically, he mentioned the lightning:card component. In the course he said,
“And if I were able to look at the source code for that component, I’m sure that I would see that their attribute title is a type Aura Component Array…”
Well, the GREAT news is that Salesforce has released all those Base Lightning Components as open source on GitHub. So now everyone can see that code and learn about the best practices that Salesforce has implemented in those components.
Anyone can clone or download the source code and then follow the directions in the README to spin up these components in a scratch org. Once you do, you can open that scratch org and using the App Launcher, browse to the Base Components app. From here, they can select one of the tabs, such as the one for the Layout Components, and see first-hand how that lightning Card component works, as well as click the link to view the source.

Is that not the coolest thing in the world? I sure think so.
I would be remiss if I did not also mention the Pluralsight course I just released called, “Building Your First Lightning Web Component for Salesforce“. It is not free, but come on, Pluralsight is soooooo worth the subscription cost.