Definition(en): These are hdr files generated by ESRI ArcGIS software. They are associated with other ArcGIS formats, .BIL, .BIP and .BSQ. All of these formats are methods of organising mapping raster image data, and the .HDR file stores the attributes of the image, eg. column and line numbers, and byte order. Esri have produced several types of GIS software (for example ArcGIS Pro, ArcPad, ArcMap), and it is not clear which software or version these signatures apply to. If you have any information on ESRI hdr files, please get in touch.