Get available modules

Question

With PHP you have the phpinfo() which lists installed modules and then from there look up what they do.

Is there a way to see what packages/modules are installed to

Answer 1

Type help() in the interpreter

then

To get a list of available modules, keywords, or topics, type "modules",
"keywords", or "topics".  Each module also comes with a one-line summary
of what it does; to list the modules whose summaries contain a given word
such as "spam", type "modules spam".                                     

help> modules