@mbrakes can you share an example Fujifilm X-Pro2 image with me so I can verify the mimetype is correct and that LibRaw is parsing it properly?
The new v1.0.0-alpha.2 (hopefully going to be released today or tomorrow) contains the latest released version of LibRaw, including .cr3 support. More details here: https://forum.photostructure.com/t/v1-0-0-alpha-1-is-out-alpha-testers-assemble/369