In reply to Maxime Beguin.

The comment for that code says “taken from WP plugin Fast Velocity Minify” which is the plugin that WP-Optimize copied code from. David Anderson mentioned this in the original story, and that seems like a reasonable explanation to me for where the code came from. But, at the same time, I don’t think it really matters much where it came from – it’s still obfuscated code, and it still something which needs to be fixed, either by attempting to “de-obfuscate” it or (better) just removing it entirely.