And how good it is, even with some flaws.
Source code is available on Mozilla's Github

LZHAM is a lossless data compression codec with a compression ratio comparable to LZMA but with 1.5~8x faster decompression.

And LZMA is one of the best ! ❤️
Link to the repository
(shared by https://sebsauvage.net/links/?KsYL2w)

Compress images and returns a 20-30 bytes long string that represents an image. It is used to wait until the image is fully loaded.

About Huffman coding