[pcre-dev] PCRE compiled format

Dear developers.
I would like to ask, if there is somewhere a documation of PCRE compiled
format, i.e. what does particular Bytes means in the array returned by
pcre_compile(). I expect that it is a kind of DFA representation.

If it is not documented anywhere, could you, please, hint me where to start
look at in order to start to understand the compiled form?

Thank you very much for your help. Kind regards,
Dan T.