The project is called QueryStorm. It uses Roslyn to offer C# (and VB.NET) support in Excel, as an alternative to VBA. I've posted about it before, but a lot has changed since then so figured I'd share an update.
The current version includes a host of new features, namely a C# debugger, support for NuGet packages, and the ability to publish Excel extensions to an "AppStore" (which is essentially a NuGet repository). The AppStore can be used by anyone with the (free) runtime component.
Another great addition is the community license, which is a free license for individuals and small companies to use. It unlocks most features, but it isn't intended for companies with more than 5 employees or over $1M in annual revenue.
I would love to hear your feedback and am happy to answer any technical questions about how QueryStorm is implemented.
Jokes aside, this is an amazing achievement, the more so for being realized by a single person working away patiently for years - truly inspiring. And it brought out a wave of nostalgia for a former life where I made a living building bespoke tools in the (pre-VBA) Excel macro language. All that and solid business sense too! I hope companies shower Antonio with money, and that Microsoft either leaves him alone or rewards him with gold and the autonomy to lead technical product development for the long term. It's rare to see such a singular combination of vision and execution, doubly so in a very mature product space belonging to a global megacorporation.