Phil is free software, where ``free'' means freedom, not without price.
The source code, scripts, libraries, functions, object code, & possibly other elements of Phil are licensed according to the terms of the Lesser Gnu Public License (LGPL). This documentation about Phil is covered by its own copyright, not the Lesser Gnu Public License.
At this point, you might be thinking ``If software I create uses Phil, must my software also be covered by the Lesser Gnu Public License?'' No. You can sell your software & legally prevent your customers from copying it if you want. I guess you can even legaly commit one of the worst crimes against freedom of speech & freedom of though; that is, you can limit your customers's rights to study & reverse engineer your program. You can't limit the rights of your customers to copy, modify, study, or use Phil under the terms of the LGPL.
It'd sure be nice if your software were free software, too.
If your program is free software, Phil's license agreement probably presents no worries for you.
You can read more about free software at the Gnu Website.