A Slot tag in HTML essentially allows a placeholder to be able to include your own markups/code. When the code is run, it shows all the pieces together. This effectively is a way to separate different parts of the code, but still have it show up as one.
These cards have been developed by my team and I with help through the use of slot tags. Before development on the cards, we decided to break up the cards into parts to be able to take advantage of scaffolding slot tags. The breakdown is as follows: icon, banner and header, card, scaffold.
When in development, the '' tag helps us be more agile in the content we want to include and it helps increase reusability of the web component.