In brief: Microsoft's massive semi-annual (usually) Windows 10 updates are the primary way for the tech giant to deliver new tools and features to the OS' userbase. However, the company is testing out a different update delivery method now: Windows Feature Experience Packs. These Packs are smaller, self-contained updates that are developed separately from the OS, and can be shipped separately as a result.
For now, Microsoft is keeping the contents of these Experience Packs very small, so it can manage scope and determine whether or not Insiders like the idea. As such, early EPs will mostly include tiny improvements and tweaks to existing Windows features and tools. They will also be relatively infrequent at first, though that will undoubtedly change over time.
As an example of what an EP might contain, here's the update log for Experience Pack 120.2212.1070.0, available now to Beta Channel Insiders:
Based on Insider feedback, you can now use the built-in screen snipping experience in Windows (WIN + SHIFT + S) to create a snip of your screen and paste it directly into a folder of your choice in File Explorer to save the screenshot there. Try it out!
Using the touch keyboard in a portrait posture on a 2-in-1 touch device now supports split keyboard mode.
There's not really much to analyze there. The snipping tool improvement will be nice (I use the feature quite a bit myself) but it's hardly game-changing, and that seems to be precisely what Microsoft is shooting for with these EPs.
It remains to be seen whether or not Microsoft will stick with the EP concept, but on paper, rolling out smaller, less controversial (and potentially less OS-breaking) updates at faster intervals could prove to be a smart move in the long run. And, if they continue to be minor, helpful additions like the two above, it's unlikely that most users will complain.
At any rate, EPs are purely optional for now. If you like the idea and want to help Microsoft test it out, though, sign up for the Windows Insider program and join the Beta Channel mentioned above. Then, ensure you have Windows 10's 20H2 19042.662 build installed, and you'll then start receiving EPs through Windows update.