Apple - Where does Photos store Live Photo videos?

On OSX 10.12.4 with Photos version 2.0 (3150.4.120) they appear to be stored in ~/Pictures/Photos Library.photoslibrary/resources/media/master/$NUM/00/jpegvideocomplement_$HEX.mov. These don't appear to be indexed by Spotlight.

I figured it out. They are stored in ~/Pictures/Photos Library.photoslibrary/resources/modelresources, though not in a folder structure that is easy to find your way around.

However, at least your video files will have the same name as photo files, for example IMG_2727.jpg and IMG_2727.mov. Once Spotlight has indexed the folder, you should be able to search by filename from the Finder, if you restrict to looking inside the Photos library folder. Or, you can use the Terminal, and cd to the Photos library folder, and then search with:

find . -name 'IMG_2727*'