When I uploaded the YII to my site via FTP, the HTMLPurifier file was rejected due to its size (over 600KB) so I had to zip it before uploading. It seems the BIG file is a merge version of many small PHP component files, with a lot of spaces and empty lines as well as many comments.
I would like to suggest YII team to use some tools to remove the unnecessary spaces, lines and comments. I also wonder if such a PHP monster will slow down the performance or not, Since PHP needs to be parsed first. A small shell script can archive that purpose.