GIMP has long been lacking in properly dealing with image meta-data -- like effectively showing useful information such as the time a photo was taken and various photograph attributes -- but now it's stepped ahead with EXIF, IPTC, and XMP support.
This image meta-data handling support for the GIMP comes via Gexiv2, a C GObject wrapper to the Exiv2 library's C++ interface. Exiv2 is an image meta-data library that supports reading and writing meta-data for these popular formats.
Gexiv2 was developed by Yorba in 2010 as they wanted to use Exiv2 within the Shotwell Photo Manager program for its image meta-data needs, but they needed to interface with the library via Vala, so this new wrapper library emerged.
Those interested in more details on the improved image meta-data support for GIMP and Gexiv2 can see this Yorba blog post. The GIMP support was been merged to mainline and will be found in the next 2.10 release.
For those curious about the other features that are coming to the GIMP, see their Roadmap Wiki.