Joe Watkins has a post on his site sharing a project he has been working on to create a debugger for PHP applications that can be installed easily and understood by those already having knowledge of PHP.

We already have several options for debugging code within the PHP ecosystem. XDebug is extremely mature software, and phpdbg has been slowly gaining traction also, if for no other reason than it's very fast to collect code coverage compared to XDebug.

[...] Debugging is a necessary part of writing code; If you disagree with this statement, then I don't know what you are talking about. [...] Using a debugger is like having an army of nano bots at your disposal, each one trained exquisitely in a top nano-bot-training-camp, they live to kill cockroaches, some of them also have mean looking tattoos, chew tobacco, and spit on the ground at the start of every sentence ...

He goes on to talk about why he made the choice to write the debugger with a PHP interface. He then gets into some of the specifics of debugging needs and links to the krakjoe/inspector repository for the tool. The README has more information about the interface and functionality than the blog post does, so if you're interested to read more, head over there.