Set charge limit for MacBooks.
This utility is written in Javascript Application Scripting (or JXA) using Apple's Script Editor.
The source code can be viewed by opening src/charge-limiter.app in Script Editor.
The companion smcutil binary (located under src/charge-limiter.app/Contents/Resources/Scripts) was copied from this repository. The source code for smcutil is also available there.
Download the latest version from the releases page.
The app is not code signed so you need to right-click on the app and select Open to bypass Gatekeeper's warning.