Store - Excel Labs

In 2024 Microsoft retired this add-in so it is no longer maintained, updated, or supported.
This is a real shame because the Formula Editor was really useful.
This add-in lets you try experimental Excel features before they become standard built-in functionality.

link - appsource.microsoft.com/en-us/product/office/wa200003696 

link - microsoft.com/en-us/garage/profiles/excel-labs/ 

Advanced Formula Environment

A full code-editor-style interface for writing and managing formulas and LAMBDA functions.
Syntax highlighting
Inline error checking
Indentation, formatting and comments
Module-based editing for named formulas
Import/export of LAMBDAs via GitHub gists

More Information

link - techcommunity.microsoft.com/blog/excelblog/advanced-formula-environment-is-becoming-excel-labs-a-microsoft-garage-project/3736518 

It also included a custom worksheet function that sends prompts to a generative AI model and returns the result directly into a cell.
It also included an agent that lets you work with Excel using natural language. You describe what you want, and Agent Mode:
Plans the steps; Executes them using tables, charts, pivottables, formulas; Refines the workbook iteratively.