In the background

`watchman`Folder watcher

● Safe to close

Watches project folders for changes on behalf of developer tools.

What it is

Watchman, from Meta, tells developer tools which files changed so they don’t have to search.

If you close it

Developer tools start it again when they need it.

● Safe to close. An app you can quit with ⌘Q. Save your work first if it asks.

From Procession’s guide, in the words the app shows.