Comment 2 for bug 1942799

XMP data is commonly included in image metadata of images that have been exported from darktable. Opening such an image in gthumb causes a non-handled std::out_of_range exception in Exiv2::Xmpdatum::write. Finally, gthumb terminates with the message

terminate called after throwing an instance of 'std::out_of_range'
  what(): basic_string::at: __n (which is 19) >= this->size() (which is 19)