1. open the project browser
2. hit the icon with a triangle/circle/square to select a category for you search criteria
3. select any animationClip
4. Choose asset Store: [n]/999+ in the project tab search titlebar
5. a few free assets are listed, pick one

you'll see on the right side, the inspector won't be listing the clip parameters, nor the asset store preview updating correctly as its waiting for something.

this does not happen in 4.7.1, but in 5.3.4 and 5.4.0b15. The regression field is debatable.