File type: Macintosh BinHex 4 Compressed Archive
HQX is a format wherein an 8-bit binary file is encoded and compressed into a 7-bit text format. This format helps to maintain the integrity of the file during internet downloads and other types of file transfers.
Combining both the resource and the data fork causes this. Double clicking the native HQX file will not result in any action unless it has been associated with any decompression.
However, if one has installed decompression programs like WinZip with decompression of all supported file extensions ticked, double clicking the HQX file will launch that program.
This extension is useful while files are transferred across different operating systems since most platforms handle ASCII easily. This helps in avoiding file corruption. If the file is not associated correctly, it might cause errors.