Are you asking because you don't know where to look or you want a convenient way to look without launching the application?
I wish Esri wouldn't use the word "patch" with ArcGIS Pro because little about the ArcGIS Pro "patches" resemble how patches worked with ArcMap. Unlike with ArcMap, each patch that has been released for ArcGIS Pro increments the tertiary version number, e.g., ArcGIS Pro 1.4 Patch 1 increments ArcGIS Pro from release 1.4 to 1.4.1. In many ways, I think the ArcGIS Pro patches are more like updates.
Since the connection between patch/update and version number is so direct, there really isn't a need for a Patchfinder program. Knowing the version installed tells you everything you need to know about patches, which wasn't the case with ArcMap.