Filter images by DNG format

With Lightroom CC's "Enhance" feature, enhanced images are duplicated in the DNG file format. However, with thousands of photos in a library, it's difficult to go through and track down every duplicate just to export them. Since we can filter by JPG/JPEG, TIFF, PNG, and others, why can we not yet filter by the DNG format? It would be a huge help for exporting and managing images in my library. It would also help with clearing out cloud space; enhanced DNGs essentially double resolution and slap a ton more metadata on the images, and the resulting files are multipe times larger than the original versions right after import. This feature likely  wouldn't be such a huge deal for those with more years of experience and more physical and cloud storage space, but for someone like me, I don't have the money yet to invest in a 1TB subscription. 20GB fills up fast.

If anyone who reads this has things to tack onto my idea, please share!