When another team member is working on a Prefab or Scene, Unity Collaborate will show an In-Progress badge. On hover you can see the team member who is currently working on the file.
There are two places where the In-Progress is visible. The first location is on the file icon in the project browser.
The second location is in the hierarchy window.
When a user publishes their changes, the icon and counter will go away.
2017–05–24 Page amended with no editorial review
New feature in Unity 2017.1 NewIn20171