Yes, Phototheca supports XMP editing and filtering what relates to keywords and descriptions. When you tag a photo with keywords in Phototheca, keywords are written into XMP and IPTC metadata sections of a JPEG file.
When you do the import of photos containing keywords in the XMP section, such keywords are recognized and let you filter by those keywords later. Also, you may do an instant search by keywords using Search box.
Read more: Work with metadata