Transcoding is generally used within the context of audio or video codecs, to convert a file from one format to another. And usually from one lossy format to another (eg: not raw uncompressed YUV420, YUV422P video or whatever that is stored in a lossless compression format). It's not clear to me why they're using it in this web page.
Additionally modern fonts are normally vector point data, no? So there's plenty of opportunity for shrinking file size by lossless compession. But I don't think that's what they're talking about here?
