WordPress.org

Does this plugin work with php4

No, this plugin does not work with php4 because the debug library pear::php_debug is php5 only.

Do I need pear installed to get this working

No, pear is not required for this plugin to work

Who is this for

I imagine this plugin will be most valuable to wordpress developers generally It will also be good for people who are having errors on their site. This plugin also measures script execution time so It is also good for people who want to measure the performance of their entire site or a specific part of their script.

Can I see the library in action?

You can see the pear demo here: Pear Demo.